Core: Drop support for IE <11, iOS <11, Firefox <65, Android Browser & PhantomJS

Also, update support comments format to match format described in:
https://github.com/jquery/contribute.jquery.org/issues/95#issuecomment-69379197
with the change from:
https://github.com/jquery/contribute.jquery.org/issues/95#issuecomment-448998379
(open-ended ranges end with `+`).

Fixes gh-3950
Fixes gh-4299
Closes gh-4347

67 files changed, 515 insertions, 1431 deletions

diff --git a/.eslintrc-browser.json b/.eslintrc-browser.json
index ffd5b6467..146745d0e 100644
--- a/.eslintrc-browser.json
+++ b/.eslintrc-browser.json
@@ -3,11 +3,8 @@
 
 	"extends": "jquery",
 
-	// Support: IE <=9 only, Android <=4.0 only
-	// The above browsers are failing a lot of tests in the ES5
-	// test suite at http://test262.ecmascript.org.
 	"parserOptions": {
-		"ecmaVersion": 3
+		"ecmaVersion": 5
 	},
 
 	// The browser env is not enabled on purpose so that code takes
diff --git a/Gruntfile.js b/Gruntfile.js
index 7fa324399..7db56b260 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -14,15 +14,7 @@ module.exports = function( grunt ) {
 
 	var fs = require( "fs" ),
 		gzip = require( "gzip-js" ),
-		isTravis = process.env.TRAVIS,
-		oldNode = /^v6\./.test( process.version );
-
-	// Support: Node.js <8
-	// Skip running tasks that dropped support for Node.js 6
-	// in those Node versions.
-	function runIfNewNode( task ) {
-		return oldNode ? "print_old_node_message:" + task : task;
-	}
+		isTravis = process.env.TRAVIS;
 
 	if ( !grunt.option( "filename" ) ) {
 		grunt.option( "filename", "jquery.js" );
@@ -123,10 +115,9 @@ module.exports = function( grunt ) {
 		testswarm: {
 			tests: [
 
-				// A special module with basic tests, meant for
-				// not fully supported environments like Android 2.3,
-				// jsdom or PhantomJS. We run it everywhere, though,
-				// to make sure tests are not broken.
+				// A special module with basic tests, meant for not fully
+				// supported environments like jsdom. We run it everywhere,
+				// though, to make sure tests are not broken.
 				"basic",
 
 				"ajax",
@@ -291,23 +282,13 @@ module.exports = function( grunt ) {
 						"dist/<%= grunt.option('filename').replace('.js', '.min.map') %>",
 					report: "min",
 					output: {
-						"ascii_only": true,
-
-						// Support: Android 4.0 only
-						// UglifyJS 3 breaks Android 4.0 if this option is not enabled.
-						// This is in lieu of setting ie8 for all of mangle, compress, and output
-						"ie8": true
+						"ascii_only": true
 					},
 					banner: "/*! jQuery v<%= pkg.version %> | " +
 						"(c) JS Foundation and other contributors | jquery.org/license */",
 					compress: {
 						"hoist_funs": false,
-						loops: false,
-
-						// Support: IE <11
-						// typeofs transformation is unsafe for IE9-10
-						// See https://github.com/mishoo/UglifyJS2/issues/2198
-						typeofs: false
+						loops: false
 					}
 				}
 			}
@@ -320,13 +301,6 @@ module.exports = function( grunt ) {
 	// Integrate jQuery specific tasks
 	grunt.loadTasks( "build/tasks" );
 
-	// Support: Node.js <8
-	// Print a message on Node.js <8 notifying the task is skipped there.
-	grunt.registerTask( "print_old_node_message", function() {
-		var task = [].slice.call( arguments ).join( ":" );
-		grunt.log.writeln( "Old Node.js detected, running the task \"" + task + "\" skipped..." );
-	} );
-
 	grunt.registerTask( "lint", [
 		"jsonlint",
 
@@ -349,10 +323,7 @@ module.exports = function( grunt ) {
 	grunt.registerTask( "test:fast", "node_smoke_tests" );
 	grunt.registerTask( "test:slow", [
 		"promises_aplus_tests",
-
-		// Support: Node.js <8
-		// Karma no longer supports Node.js <8 as it relies on async-await internally.
-		runIfNewNode( "karma:jsdom" )
+		"karma:jsdom"
 	] );
 
 	grunt.registerTask( "test", [
diff --git a/src/ajax.js b/src/ajax.js
index 4cbefabaa..9db26f66c 100644
--- a/src/ajax.js
+++ b/src/ajax.js
@@ -1,7 +1,6 @@
 define( [
 	"./core",
 	"./var/document",
-	"./var/isFunction",
 	"./var/rnothtmlwhite",
 	"./ajax/var/location",
 	"./ajax/var/nonce",
@@ -12,7 +11,7 @@ define( [
 	"./event/trigger",
 	"./deferred",
 	"./serialize" // jQuery.param
-], function( jQuery, document, isFunction, rnothtmlwhite, location, nonce, rquery ) {
+], function( jQuery, document, rnothtmlwhite, location, nonce, rquery ) {
 
 "use strict";
 
@@ -67,7 +66,7 @@ function addToPrefiltersOrTransports( structure ) {
 			i = 0,
 			dataTypes = dataTypeExpression.toLowerCase().match( rnothtmlwhite ) || [];
 
-		if ( isFunction( func ) ) {
+		if ( typeof func === "function" ) {
 
 			// For each dataType in the dataTypeExpression
 			while ( ( dataType = dataTypes[ i++ ] ) ) {
@@ -541,13 +540,13 @@ jQuery.extend( {
 		if ( s.crossDomain == null ) {
 			urlAnchor = document.createElement( "a" );
 
-			// Support: IE <=8 - 11, Edge 12 - 15
+			// Support: IE <=8 - 11+, Edge 12 - 17 only
 			// IE throws exception on accessing the href property if url is malformed,
 			// e.g. http://example.com:80x/
 			try {
 				urlAnchor.href = s.url;
 
-				// Support: IE <=8 - 11 only
+				// Support: IE <=8 - 11+
 				// Anchor's host property isn't correctly set when s.url is relative
 				urlAnchor.href = urlAnchor.href;
 				s.crossDomain = originAnchor.protocol + "//" + originAnchor.host !==
@@ -837,7 +836,7 @@ jQuery.each( [ "get", "post" ], function( i, method ) {
 	jQuery[ method ] = function( url, data, callback, type ) {
 
 		// Shift arguments if data argument was omitted
-		if ( isFunction( data ) ) {
+		if ( typeof data === "function" ) {
 			type = type || callback;
 			callback = data;
 			data = undefined;
diff --git a/src/ajax/jsonp.js b/src/ajax/jsonp.js
index 28ae0365d..dbdb4dbb8 100644
--- a/src/ajax/jsonp.js
+++ b/src/ajax/jsonp.js
@@ -1,10 +1,9 @@
 define( [
 	"../core",
-	"../var/isFunction",
 	"./var/nonce",
 	"./var/rquery",
 	"../ajax"
-], function( jQuery, isFunction, nonce, rquery ) {
+], function( jQuery, nonce, rquery ) {
 
 "use strict";
 
@@ -37,7 +36,7 @@ jQuery.ajaxPrefilter( "json jsonp", function( s, originalSettings, jqXHR ) {
 	if ( jsonProp || s.dataTypes[ 0 ] === "jsonp" ) {
 
 		// Get callback name, remembering preexisting value associated with it
-		callbackName = s.jsonpCallback = isFunction( s.jsonpCallback ) ?
+		callbackName = s.jsonpCallback = typeof s.jsonpCallback === "function" ?
 			s.jsonpCallback() :
 			s.jsonpCallback;
 
@@ -88,7 +87,7 @@ jQuery.ajaxPrefilter( "json jsonp", function( s, originalSettings, jqXHR ) {
 			}
 
 			// Call if it was a function and we have a response
-			if ( responseContainer && isFunction( overwritten ) ) {
+			if ( responseContainer && typeof overwritten === "function" ) {
 				overwritten( responseContainer[ 0 ] );
 			}
 
diff --git a/src/ajax/load.js b/src/ajax/load.js
index defdb0174..574d6b4a7 100644
--- a/src/ajax/load.js
+++ b/src/ajax/load.js
@@ -1,13 +1,12 @@
 define( [
 	"../core",
 	"../core/stripAndCollapse",
-	"../var/isFunction",
 	"../core/parseHTML",
 	"../ajax",
 	"../traversing",
 	"../manipulation",
 	"../selector"
-], function( jQuery, stripAndCollapse, isFunction ) {
+], function( jQuery, stripAndCollapse ) {
 
 "use strict";
 
@@ -25,7 +24,7 @@ jQuery.fn.load = function( url, params, callback ) {
 	}
 
 	// If it's a function
-	if ( isFunction( params ) ) {
+	if ( typeof params === "function" ) {
 
 		// We assume that it's the callback
 		callback = params;
diff --git a/src/ajax/parseXML.js b/src/ajax/parseXML.js
index acf7ab259..0bdc49a7c 100644
--- a/src/ajax/parseXML.js
+++ b/src/ajax/parseXML.js
@@ -11,7 +11,7 @@ jQuery.parseXML = function( data ) {
 		return null;
 	}
 
-	// Support: IE 9 - 11 only
+	// Support: IE 9 - 11+
 	// IE throws on parseFromString with invalid input.
 	try {
 		xml = ( new window.DOMParser() ).parseFromString( data, "text/xml" );
diff --git a/src/ajax/xhr.js b/src/ajax/xhr.js
index 4a31171ac..16a2ac3d8 100644
--- a/src/ajax/xhr.js
+++ b/src/ajax/xhr.js
@@ -1,8 +1,7 @@
 define( [
 	"../core",
-	"../var/support",
 	"../ajax"
-], function( jQuery, support ) {
+], function( jQuery ) {
 
 "use strict";
 
@@ -15,156 +14,109 @@ jQuery.ajaxSettings.xhr = function() {
 var xhrSuccessStatus = {
 
 		// File protocol always yields status code 0, assume 200
-		0: 200,
-
-		// Support: IE <=9 only
-		// #1450: sometimes IE returns 1223 when it should be 204
-		1223: 204
-	},
-	xhrSupported = jQuery.ajaxSettings.xhr();
-
-support.cors = !!xhrSupported && ( "withCredentials" in xhrSupported );
-support.ajax = xhrSupported = !!xhrSupported;
+		0: 200
+	};
 
 jQuery.ajaxTransport( function( options ) {
-	var callback, errorCallback;
+	var callback;
 
 	// Cross domain only allowed if supported through XMLHttpRequest
-	if ( support.cors || xhrSupported && !options.crossDomain ) {
-		return {
-			send: function( headers, complete ) {
-				var i,
-					xhr = options.xhr();
-
-				xhr.open(
-					options.type,
-					options.url,
-					options.async,
-					options.username,
-					options.password
-				);
-
-				// Apply custom fields if provided
-				if ( options.xhrFields ) {
-					for ( i in options.xhrFields ) {
-						xhr[ i ] = options.xhrFields[ i ];
-					}
+	return {
+		send: function( headers, complete ) {
+			var i,
+				xhr = options.xhr();
+
+			xhr.open(
+				options.type,
+				options.url,
+				options.async,
+				options.username,
+				options.password
+			);
+
+			// Apply custom fields if provided
+			if ( options.xhrFields ) {
+				for ( i in options.xhrFields ) {
+					xhr[ i ] = options.xhrFields[ i ];
 				}
+			}
 
-				// Override mime type if needed
-				if ( options.mimeType && xhr.overrideMimeType ) {
-					xhr.overrideMimeType( options.mimeType );
-				}
+			// Override mime type if needed
+			if ( options.mimeType && xhr.overrideMimeType ) {
+				xhr.overrideMimeType( options.mimeType );
+			}
 
-				// X-Requested-With header
-				// For cross-domain requests, seeing as conditions for a preflight are
-				// akin to a jigsaw puzzle, we simply never set it to be sure.
-				// (it can always be set on a per-request basis or even using ajaxSetup)
-				// For same-domain requests, won't change header if already provided.
-				if ( !options.crossDomain && !headers[ "X-Requested-With" ] ) {
-					headers[ "X-Requested-With" ] = "XMLHttpRequest";
-				}
+			// X-Requested-With header
+			// For cross-domain requests, seeing as conditions for a preflight are
+			// akin to a jigsaw puzzle, we simply never set it to be sure.
+			// (it can always be set on a per-request basis or even using ajaxSetup)
+			// For same-domain requests, won't change header if already provided.
+			if ( !options.crossDomain && !headers[ "X-Requested-With" ] ) {
+				headers[ "X-Requested-With" ] = "XMLHttpRequest";
+			}
 
-				// Set headers
-				for ( i in headers ) {
-					xhr.setRequestHeader( i, headers[ i ] );
-				}
+			// Set headers
+			for ( i in headers ) {
+				xhr.setRequestHeader( i, headers[ i ] );
+			}
 
-				// Callback
-				callback = function( type ) {
-					return function() {
-						if ( callback ) {
-							callback = errorCallback = xhr.onload =
-								xhr.onerror = xhr.onabort = xhr.ontimeout =
-									xhr.onreadystatechange = null;
-
-							if ( type === "abort" ) {
-								xhr.abort();
-							} else if ( type === "error" ) {
-
-								// Support: IE <=9 only
-								// On a manual native abort, IE9 throws
-								// errors on any property access that is not readyState
-								if ( typeof xhr.status !== "number" ) {
-									complete( 0, "error" );
-								} else {
-									complete(
-
-										// File: protocol always yields status 0; see #8605, #14207
-										xhr.status,
-										xhr.statusText
-									);
-								}
-							} else {
-								complete(
-									xhrSuccessStatus[ xhr.status ] || xhr.status,
-									xhr.statusText,
-
-									// Support: IE <=9 only
-									// IE9 has no XHR2 but throws on binary (trac-11426)
-									// For XHR2 non-text, let the caller handle it (gh-2498)
-									( xhr.responseType || "text" ) !== "text"  ||
-									typeof xhr.responseText !== "string" ?
-										{ binary: xhr.response } :
-										{ text: xhr.responseText },
-									xhr.getAllResponseHeaders()
-								);
-							}
+			// Callback
+			callback = function( type ) {
+				return function() {
+					if ( callback ) {
+						callback = xhr.onload = xhr.onerror = xhr.onabort = xhr.ontimeout = null;
+
+						if ( type === "abort" ) {
+							xhr.abort();
+						} else if ( type === "error" ) {
+							complete(
+
+								// File: protocol always yields status 0; see #8605, #14207
+								xhr.status,
+								xhr.statusText
+							);
+						} else {
+							complete(
+								xhrSuccessStatus[ xhr.status ] || xhr.status,
+								xhr.statusText,
+
+								// For XHR2 non-text, let the caller handle it (gh-2498)
+								( xhr.responseType || "text" ) === "text" ?
+									{ text: xhr.responseText } :
+									{ binary: xhr.response },
+								xhr.getAllResponseHeaders()
+							);
 						}
-					};
+					}
 				};
+			};
 
-				// Listen to events
-				xhr.onload = callback();
-				errorCallback = xhr.onerror = xhr.ontimeout = callback( "error" );
-
-				// Support: IE 9 only
-				// Use onreadystatechange to replace onabort
-				// to handle uncaught aborts
-				if ( xhr.onabort !== undefined ) {
-					xhr.onabort = errorCallback;
-				} else {
-					xhr.onreadystatechange = function() {
-
-						// Check readyState before timeout as it changes
-						if ( xhr.readyState === 4 ) {
-
-							// Allow onerror to be called first,
-							// but that will not handle a native abort
-							// Also, save errorCallback to a variable
-							// as xhr.onerror cannot be accessed
-							window.setTimeout( function() {
-								if ( callback ) {
-									errorCallback();
-								}
-							} );
-						}
-					};
-				}
-
-				// Create the abort callback
-				callback = callback( "abort" );
+			// Listen to events
+			xhr.onload = callback();
+			xhr.onabort = xhr.onerror = xhr.ontimeout = callback( "error" );
 
-				try {
+			// Create the abort callback
+			callback = callback( "abort" );
 
-					// Do send the request (this may raise an exception)
-					xhr.send( options.hasContent && options.data || null );
-				} catch ( e ) {
+			try {
 
-					// #14683: Only rethrow if this hasn't been notified as an error yet
-					if ( callback ) {
-						throw e;
-					}
-				}
-			},
+				// Do send the request (this may raise an exception)
+				xhr.send( options.hasContent && options.data || null );
+			} catch ( e ) {
 
-			abort: function() {
+				// #14683: Only rethrow if this hasn't been notified as an error yet
 				if ( callback ) {
-					callback();
+					throw e;
 				}
 			}
-		};
-	}
+		},
+
+		abort: function() {
+			if ( callback ) {
+				callback();
+			}
+		}
+	};
 } );
 
 } );
diff --git a/src/attributes/classes.js b/src/attributes/classes.js
index 0c90a8dff..f1571eb5d 100644
--- a/src/attributes/classes.js
+++ b/src/attributes/classes.js
@@ -1,11 +1,10 @@
 define( [
 	"../core",
 	"../core/stripAndCollapse",
-	"../var/isFunction",
 	"../var/rnothtmlwhite",
 	"../data/var/dataPriv",
 	"../core/init"
-], function( jQuery, stripAndCollapse, isFunction, rnothtmlwhite, dataPriv ) {
+], function( jQuery, stripAndCollapse, rnothtmlwhite, dataPriv ) {
 
 "use strict";
 
@@ -28,7 +27,7 @@ jQuery.fn.extend( {
 		var classes, elem, cur, curValue, clazz, j, finalValue,
 			i = 0;
 
-		if ( isFunction( value ) ) {
+		if ( typeof value === "function" ) {
 			return this.each( function( j ) {
 				jQuery( this ).addClass( value.call( this, j, getClass( this ) ) );
 			} );
@@ -65,7 +64,7 @@ jQuery.fn.extend( {
 		var classes, elem, cur, curValue, clazz, j, finalValue,
 			i = 0;
 
-		if ( isFunction( value ) ) {
+		if ( typeof value === "function" ) {
 			return this.each( function( j ) {
 				jQuery( this ).removeClass( value.call( this, j, getClass( this ) ) );
 			} );
@@ -114,7 +113,7 @@ jQuery.fn.extend( {
 			return stateVal ? this.addClass( value ) : this.removeClass( value );
 		}
 
-		if ( isFunction( value ) ) {
+		if ( typeof value === "function" ) {
 			return this.each( function( i ) {
 				jQuery( this ).toggleClass(
 					value.call( this, i, getClass( this ), stateVal ),
diff --git a/src/attributes/prop.js b/src/attributes/prop.js
index 49ac244df..8ada707f4 100644
--- a/src/attributes/prop.js
+++ b/src/attributes/prop.js
@@ -59,7 +59,7 @@ jQuery.extend( {
 		tabIndex: {
 			get: function( elem ) {
 
-				// Support: IE <=9 - 11 only
+				// Support: IE <=9 - 11+
 				// elem.tabIndex doesn't always return the
 				// correct value when it hasn't been explicitly set
 				// https://web.archive.org/web/20141116233347/http://fluidproject.org/blog/2008/01/09/getting-setting-and-removing-tabindex-values-with-javascript/
@@ -89,7 +89,7 @@ jQuery.extend( {
 	}
 } );
 
-// Support: IE <=11 only
+// Support: IE <=11+
 // Accessing the selectedIndex property
 // forces the browser to respect setting selected
 // on the option
@@ -101,23 +101,23 @@ if ( !support.optSelected ) {
 	jQuery.propHooks.selected = {
 		get: function( elem ) {
 
-			/* eslint no-unused-expressions: "off" */
-
 			var parent = elem.parentNode;
 			if ( parent && parent.parentNode ) {
+				// eslint-disable-next-line no-unused-expressions
 				parent.parentNode.selectedIndex;
 			}
 			return null;
 		},
 		set: function( elem ) {
 
-			/* eslint no-unused-expressions: "off" */
 
 			var parent = elem.parentNode;
 			if ( parent ) {
+				// eslint-disable-next-line no-unused-expressions
 				parent.selectedIndex;
 
 				if ( parent.parentNode ) {
+					// eslint-disable-next-line no-unused-expressions
 					parent.parentNode.selectedIndex;
 				}
 			}
diff --git a/src/attributes/support.js b/src/attributes/support.js
index af60e9694..78d0040a9 100644
--- a/src/attributes/support.js
+++ b/src/attributes/support.js
@@ -12,15 +12,11 @@ define( [
 
 	input.type = "checkbox";
 
-	// Support: Android <=4.3 only
-	// Default value for a checkbox should be "on"
-	support.checkOn = input.value !== "";
-
-	// Support: IE <=11 only
+	// Support: IE <=11+
 	// Must access selectedIndex to make default options select
 	support.optSelected = opt.selected;
 
-	// Support: IE <=11 only
+	// Support: IE <=11+
 	// An input loses its value after becoming a radio
 	input = document.createElement( "input" );
 	input.value = "t";
diff --git a/src/attributes/val.js b/src/attributes/val.js
index c719b34b3..f7d6cf190 100644
--- a/src/attributes/val.js
+++ b/src/attributes/val.js
@@ -1,12 +1,10 @@
 define( [
 	"../core",
 	"../core/stripAndCollapse",
-	"./support",
 	"../core/nodeName",
-	"../var/isFunction",
 
 	"../core/init"
-], function( jQuery, stripAndCollapse, support, nodeName, isFunction ) {
+], function( jQuery, stripAndCollapse, nodeName ) {
 
 "use strict";
 
@@ -43,7 +41,7 @@ jQuery.fn.extend( {
 			return;
 		}
 
-		valueIsFunction = isFunction( value );
+		valueIsFunction = typeof value === "function";
 
 		return this.each( function( i ) {
 			var val;
@@ -90,7 +88,7 @@ jQuery.extend( {
 				return val != null ?
 					val :
 
-					// Support: IE <=10 - 11 only
+					// Support: IE <=10 - 11+
 					// option.text throws exceptions (#14686, #14858)
 					// Strip and collapse whitespace
 					// https://html.spec.whatwg.org/#strip-and-collapse-whitespace
@@ -117,9 +115,7 @@ jQuery.extend( {
 				for ( ; i < max; i++ ) {
 					option = options[ i ];
 
-					// Support: IE <=9 only
-					// IE8-9 doesn't update selected after form reset (#2551)
-					if ( ( option.selected || i === index ) &&
+					if ( option.selected &&
 
 							// Don't return options that are disabled or in a disabled optgroup
 							!option.disabled &&
@@ -181,11 +177,6 @@ jQuery.each( [ "radio", "checkbox" ], function() {
 			}
 		}
 	};
-	if ( !support.checkOn ) {
-		jQuery.valHooks[ this ].get = function( elem ) {
-			return elem.getAttribute( "value" ) === null ? "on" : elem.value;
-		};
-	}
 } );
 
 } );
diff --git a/src/callbacks.js b/src/callbacks.js
index 6cf54031e..140c4979e 100644
--- a/src/callbacks.js
+++ b/src/callbacks.js
@@ -1,9 +1,8 @@
 define( [
 	"./core",
 	"./core/toType",
-	"./var/isFunction",
 	"./var/rnothtmlwhite"
-], function( jQuery, toType, isFunction, rnothtmlwhite ) {
+], function( jQuery, toType, rnothtmlwhite ) {
 
 "use strict";
 
@@ -127,7 +126,7 @@ jQuery.Callbacks = function( options ) {
 
 					( function add( args ) {
 						jQuery.each( args, function( _, arg ) {
-							if ( isFunction( arg ) ) {
+							if ( typeof arg === "function" ) {
 								if ( !options.unique || !self.has( arg ) ) {
 									list.push( arg );
 								}
diff --git a/src/core.js b/src/core.js
index 3ef92d48f..5a5c7469e 100644
--- a/src/core.js
+++ b/src/core.js
@@ -15,14 +15,14 @@ define( [
 	"./var/hasOwn",
 	"./var/fnToString",
 	"./var/ObjectFunctionString",
+	"./var/trim",
 	"./var/support",
-	"./var/isFunction",
 	"./var/isWindow",
 	"./core/DOMEval",
 	"./core/toType"
 ], function( arr, document, getProto, slice, concat, push, indexOf,
 	class2type, toString, hasOwn, fnToString, ObjectFunctionString,
-	support, isFunction, isWindow, DOMEval, toType ) {
+	trim, support, isWindow, DOMEval, toType ) {
 
 "use strict";
 
@@ -35,11 +35,7 @@ var
 		// The jQuery object is actually just the init constructor 'enhanced'
 		// Need init if jQuery is called (just allow error to be thrown if not included)
 		return new jQuery.fn.init( selector, context );
-	},
-
-	// Support: Android <=4.0 only
-	// Make sure we trim BOM and NBSP
-	rtrim = /^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g;
+	};
 
 jQuery.fn = jQuery.prototype = {
 
@@ -139,7 +135,7 @@ jQuery.extend = jQuery.fn.extend = function() {
 	}
 
 	// Handle case when target is a string or something (possible in deep copy)
-	if ( typeof target !== "object" && !isFunction( target ) ) {
+	if ( typeof target !== "object" && typeof target !== "function" ) {
 		target = {};
 	}
 
@@ -264,11 +260,8 @@ jQuery.extend( {
 		return obj;
 	},
 
-	// Support: Android <=4.0 only
 	trim: function( text ) {
-		return text == null ?
-			"" :
-			( text + "" ).replace( rtrim, "" );
+		return text == null ? "" : trim.call( text );
 	},
 
 	// results is for internal usage only
@@ -293,8 +286,6 @@ jQuery.extend( {
 		return arr == null ? -1 : indexOf.call( arr, elem, i );
 	},
 
-	// Support: Android <=4.0 only, PhantomJS 1 only
-	// push.apply(_, arraylike) throws on ancient WebKit
 	merge: function( first, second ) {
 		var len = +second.length,
 			j = 0,
@@ -380,14 +371,10 @@ function( i, name ) {
 
 function isArrayLike( obj ) {
 
-	// Support: real iOS 8.2 only (not reproducible in simulator)
-	// `in` check used to prevent JIT error (gh-2145)
-	// hasOwn isn't used here due to false negatives
-	// regarding Nodelist length in IE
-	var length = !!obj && "length" in obj && obj.length,
+	var length = !!obj && obj.length,
 		type = toType( obj );
 
-	if ( isFunction( obj ) || isWindow( obj ) ) {
+	if ( typeof obj === "function" || isWindow( obj ) ) {
 		return false;
 	}
 
diff --git a/src/core/DOMEval.js b/src/core/DOMEval.js
index 59f6e0247..df83cca52 100644
--- a/src/core/DOMEval.js
+++ b/src/core/DOMEval.js
@@ -20,7 +20,7 @@ define( [
 		if ( node ) {
 			for ( i in preservedScriptAttributes ) {
 
-				// Support: Firefox 64+, Edge 18+
+				// Support: Firefox <=64 - 66+, Edge <=18+
 				// Some browsers don't support the "nonce" property on scripts.
 				// On the other hand, just using `getAttribute` is not enough as
 				// the `nonce` attribute is reset to an empty string whenever it
diff --git a/src/core/access.js b/src/core/access.js
index 842c4a42b..f600600d5 100644
--- a/src/core/access.js
+++ b/src/core/access.js
@@ -1,8 +1,7 @@
 define( [
 	"../core",
-	"../core/toType",
-	"../var/isFunction"
-], function( jQuery, toType, isFunction ) {
+	"../core/toType"
+], function( jQuery, toType ) {
 
 "use strict";
 
@@ -24,7 +23,7 @@ var access = function( elems, fn, key, value, chainable, emptyGet, raw ) {
 	} else if ( value !== undefined ) {
 		chainable = true;
 
-		if ( !isFunction( value ) ) {
+		if ( typeof value !== "function" ) {
 			raw = true;
 		}
 
diff --git a/src/core/init.js b/src/core/init.js
index 8865238c8..71f30e926 100644
--- a/src/core/init.js
+++ b/src/core/init.js
@@ -2,11 +2,10 @@
 define( [
 	"../core",
 	"../var/document",
-	"../var/isFunction",
 	"./var/rsingleTag",
 
 	"../traversing/findFilter"
-], function( jQuery, document, isFunction, rsingleTag ) {
+], function( jQuery, document, rsingleTag ) {
 
 "use strict";
 
@@ -64,7 +63,7 @@ var rootjQuery,
 						for ( match in context ) {
 
 							// Properties of context are called as methods if possible
-							if ( isFunction( this[ match ] ) ) {
+							if ( typeof this[ match ] === "function" ) {
 								this[ match ]( context[ match ] );
 
 							// ...and otherwise set as attributes
@@ -107,7 +106,7 @@ var rootjQuery,
 
 		// HANDLE: $(function)
 		// Shortcut for document ready
-		} else if ( isFunction( selector ) ) {
+		} else if ( typeof selector === "function" ) {
 			return root.ready !== undefined ?
 				root.ready( selector ) :
 
diff --git a/src/core/isAttached.js b/src/core/isAttached.js
index efa2465a9..1acf15714 100644
--- a/src/core/isAttached.js
+++ b/src/core/isAttached.js
@@ -10,8 +10,9 @@ define( [
 		},
 		composed = { composed: true };
 
+	// Support: IE 9 - 11+, Edge 12 - 18+
 	// Check attachment across shadow DOM boundaries when possible (gh-3504)
-	if ( documentElement.attachShadow ) {
+	if ( documentElement.getRootNode ) {
 		isAttached = function( elem ) {
 			return jQuery.contains( elem.ownerDocument, elem ) ||
 				elem.getRootNode( composed ) === elem.ownerDocument;
diff --git a/src/core/parseHTML.js b/src/core/parseHTML.js
index 21ff6bfa7..8c5268fb1 100644
--- a/src/core/parseHTML.js
+++ b/src/core/parseHTML.js
@@ -2,11 +2,8 @@ define( [
 	"../core",
 	"../var/document",
 	"./var/rsingleTag",
-	"../manipulation/buildFragment",
-
-	// This is the only module that needs core/support
-	"./support"
-], function( jQuery, document, rsingleTag, buildFragment, support ) {
+	"../manipulation/buildFragment"
+], function( jQuery, document, rsingleTag, buildFragment ) {
 
 "use strict";
 
@@ -29,18 +26,14 @@ jQuery.parseHTML = function( data, context, keepScripts ) {
 
 		// Stop scripts or inline event handlers from being executed immediately
 		// by using document.implementation
-		if ( support.createHTMLDocument ) {
-			context = document.implementation.createHTMLDocument( "" );
-
-			// Set the base href for the created document
-			// so any parsed elements with URLs
-			// are based on the document's URL (gh-2965)
-			base = context.createElement( "base" );
-			base.href = document.location.href;
-			context.head.appendChild( base );
-		} else {
-			context = document;
-		}
+		context = document.implementation.createHTMLDocument( "" );
+
+		// Set the base href for the created document
+		// so any parsed elements with URLs
+		// are based on the document's URL (gh-2965)
+		base = context.createElement( "base" );
+		base.href = document.location.href;
+		context.head.appendChild( base );
 	}
 
 	parsed = rsingleTag.exec( data );
diff --git a/src/core/ready-no-deferred.js b/src/core/ready-no-deferred.js
index 4428020ef..2c3fc1b84 100644
--- a/src/core/ready-no-deferred.js
+++ b/src/core/ready-no-deferred.js
@@ -1,8 +1,7 @@
 define( [
 	"../core",
-	"../var/document",
-	"../var/isFunction"
-], function( jQuery, document, isFunction ) {
+	"../var/document"
+], function( jQuery, document ) {
 
 "use strict";
 
@@ -53,7 +52,7 @@ jQuery.extend( {
 
 			while ( readyCallbacks.length ) {
 				fn = readyCallbacks.shift();
-				if ( isFunction( fn ) ) {
+				if ( typeof fn === "function" ) {
 					executeReady( fn );
 				}
 			}
@@ -77,10 +76,7 @@ function completed() {
 
 // Catch cases where $(document).ready() is called
 // after the browser event has already occurred.
-// Support: IE9-10 only
-// Older IE sometimes signals "interactive" too soon
-if ( document.readyState === "complete" ||
-	( document.readyState !== "loading" && !document.documentElement.doScroll ) ) {
+if ( document.readyState !== "loading" ) {
 
 	// Handle it asynchronously to allow scripts the opportunity to delay ready
 	window.setTimeout( jQuery.ready );
diff --git a/src/core/ready.js b/src/core/ready.js
index 794feeec0..3abb6c03a 100644
--- a/src/core/ready.js
+++ b/src/core/ready.js
@@ -66,10 +66,7 @@ function completed() {
 
 // Catch cases where $(document).ready() is called
 // after the browser event has already occurred.
-// Support: IE <=9 - 10 only
-// Older IE sometimes signals "interactive" too soon
-if ( document.readyState === "complete" ||
-	( document.readyState !== "loading" && !document.documentElement.doScroll ) ) {
+if ( document.readyState !== "loading" ) {
 
 	// Handle it asynchronously to allow scripts the opportunity to delay ready
 	window.setTimeout( jQuery.ready );
diff --git a/src/core/support.js b/src/core/support.js
deleted file mode 100644
index 13ae02f08..000000000
--- a/src/core/support.js
+++ /dev/null
@@ -1,20 +0,0 @@
-define( [
-	"../var/document",
-	"../var/support"
-], function( document, support ) {
-
-"use strict";
-
-// Support: Safari 8 only
-// In Safari 8 documents created via document.implementation.createHTMLDocument
-// collapse sibling forms: the second one becomes a child of the first one.
-// Because of that, this security measure has to be disabled in Safari 8.
-// https://bugs.webkit.org/show_bug.cgi?id=137337
-support.createHTMLDocument = ( function() {
-	var body = document.implementation.createHTMLDocument( "" ).body;
-	body.innerHTML = "<form></form><form></form>";
-	return body.childNodes.length === 2;
-} )();
-
-return support;
-} );
diff --git a/src/core/toType.js b/src/core/toType.js
index c77ba95ad..c555ef9df 100644
--- a/src/core/toType.js
+++ b/src/core/toType.js
@@ -10,8 +10,7 @@ function toType( obj ) {
 		return obj + "";
 	}
 
-	// Support: Android <=2.3 only (functionish RegExp)
-	return typeof obj === "object" || typeof obj === "function" ?
+	return typeof obj === "object" ?
 		class2type[ toString.call( obj ) ] || "object" :
 		typeof obj;
 }
diff --git a/src/css.js b/src/css.js
index c92fc684a..91c42624e 100644
--- a/src/css.js
+++ b/src/css.js
@@ -10,7 +10,6 @@ define( [
 	"./css/var/swap",
 	"./css/curCSS",
 	"./css/adjustCSS",
-	"./css/addGetHookIf",
 	"./css/support",
 	"./css/finalPropName",
 
@@ -18,7 +17,7 @@ define( [
 	"./core/ready",
 	"./selector" // contains
 ], function( jQuery, access, rcssNum, rnumnonpx, cssExpand, isAutoPx, cssCamelCase,
-	getStyles, swap, curCSS, adjustCSS, addGetHookIf, support, finalPropName ) {
+	getStyles, swap, curCSS, adjustCSS, support, finalPropName ) {
 
 "use strict";
 
@@ -130,7 +129,6 @@ function getWidthOrHeight( elem, dimension, extra ) {
 		val = curCSS( elem, dimension, styles ),
 		offsetProp = "offset" + dimension[ 0 ].toUpperCase() + dimension.slice( 1 );
 
-	// Support: Firefox <=54
 	// Return a confounding non-pixel value or feign ignorance, as appropriate.
 	if ( rnumnonpx.test( val ) ) {
 		if ( !extra ) {
@@ -142,15 +140,11 @@ function getWidthOrHeight( elem, dimension, extra ) {
 
 	// Fall back to offsetWidth/offsetHeight when value is "auto"
 	// This happens for inline elements with no explicit setting (gh-3571)
-	// Support: Android <=4.1 - 4.3 only
-	// Also use offsetWidth/offsetHeight for misreported inline dimensions (gh-3602)
-	// Support: IE 9-11 only
+	// Support: IE 9 - 11+
 	// Also use offsetWidth/offsetHeight for when box sizing is unreliable
 	// We use getClientRects() to check for hidden/disconnected.
 	// In those cases, the computed value can be trusted to be border-box
-	if ( ( !support.boxSizingReliable() && isBorderBox ||
-		val === "auto" ||
-		!parseFloat( val ) && jQuery.css( elem, "display", false, styles ) === "inline" ) &&
+	if ( ( !support.boxSizingReliable() && isBorderBox || val === "auto" ) &&
 		elem.getClientRects().length ) {
 
 		isBorderBox = jQuery.css( elem, "boxSizing", false, styles ) === "border-box";
@@ -324,10 +318,10 @@ jQuery.each( [ "height", "width" ], function( i, dimension ) {
 				// but it must have a current display style that would benefit
 				return rdisplayswap.test( jQuery.css( elem, "display" ) ) &&
 
-					// Support: Safari 8+
-					// Table columns in Safari have non-zero offsetWidth & zero
+					// Support: Safari <=8 - 12+, Chrome <=73+
+					// Table columns in WebKit/Blink have non-zero offsetWidth & zero
 					// getBoundingClientRect().width unless display is changed.
-					// Support: IE <=11 only
+					// Support: IE <=11+
 					// Running getBoundingClientRect on a disconnected node
 					// in IE throws an error.
 					( !elem.getClientRects().length || !elem.getBoundingClientRect().width ) ?
@@ -342,14 +336,8 @@ jQuery.each( [ "height", "width" ], function( i, dimension ) {
 			var matches,
 				styles = getStyles( elem ),
 
-				// Only read styles.position if the test has a chance to fail
-				// to avoid forcing a reflow.
-				scrollboxSizeBuggy = !support.scrollboxSize() &&
-					styles.position === "absolute",
-
 				// To avoid forcing a reflow, only fetch boxSizing if we need it (gh-3991)
-				boxSizingNeeded = scrollboxSizeBuggy || extra,
-				isBorderBox = boxSizingNeeded &&
+				isBorderBox = extra &&
 					jQuery.css( elem, "boxSizing", false, styles ) === "border-box",
 				subtract = extra ?
 					boxModelAdjustment(
@@ -361,17 +349,6 @@ jQuery.each( [ "height", "width" ], function( i, dimension ) {
 					) :
 					0;
 
-			// Account for unreliable border-box dimensions by comparing offset* to computed and
-			// faking a content-box to get border and padding (gh-3699)
-			if ( isBorderBox && scrollboxSizeBuggy ) {
-				subtract -= Math.ceil(
-					elem[ "offset" + dimension[ 0 ].toUpperCase() + dimension.slice( 1 ) ] -
-					parseFloat( styles[ dimension ] ) -
-					boxModelAdjustment( elem, dimension, "border", false, styles ) -
-					0.5
-				);
-			}
-
 			// Convert to pixels if value adjustment is needed
 			if ( subtract && ( matches = rcssNum.exec( value ) ) &&
 				( matches[ 3 ] || "px" ) !== "px" ) {
@@ -385,19 +362,6 @@ jQuery.each( [ "height", "width" ], function( i, dimension ) {
 	};
 } );
 
-jQuery.cssHooks.marginLeft = addGetHookIf( support.reliableMarginLeft,
-	function( elem, computed ) {
-		if ( computed ) {
-			return ( parseFloat( curCSS( elem, "marginLeft" ) ) ||
-				elem.getBoundingClientRect().left -
-					swap( elem, { marginLeft: 0 }, function() {
-						return elem.getBoundingClientRect().left;
-					} )
-				) + "px";
-		}
-	}
-);
-
 // These hooks are used by animate to expand properties
 jQuery.each( {
 	margin: "",
diff --git a/src/css/addGetHookIf.js b/src/css/addGetHookIf.js
deleted file mode 100644
index e4bb49a67..000000000
--- a/src/css/addGetHookIf.js
+++ /dev/null
@@ -1,26 +0,0 @@
-define( function() {
-
-"use strict";
-
-function addGetHookIf( conditionFn, hookFn ) {
-
-	// Define the hook, we'll check on the first run if it's really needed.
-	return {
-		get: function() {
-			if ( conditionFn() ) {
-
-				// Hook not needed (or it's not possible to use it due
-				// to missing dependency), remove it.
-				delete this.get;
-				return;
-			}
-
-			// Hook needed; redefine it so that the support test is not executed again.
-			return ( this.get = hookFn ).apply( this, arguments );
-		}
-	};
-}
-
-return addGetHookIf;
-
-} );
diff --git a/src/css/adjustCSS.js b/src/css/adjustCSS.js
index 4e3e6c37a..5341a7890 100644
--- a/src/css/adjustCSS.js
+++ b/src/css/adjustCSS.js
@@ -26,7 +26,7 @@ function adjustCSS( elem, prop, valueParts, tween ) {
 
 	if ( initialInUnit && initialInUnit[ 3 ] !== unit ) {
 
-		// Support: Firefox <=54
+		// Support: Firefox <=54 - 66+
 		// Halve the iteration target value to prevent interference from CSS upper bounds (gh-2144)
 		initial = initial / 2;
 
diff --git a/src/css/curCSS.js b/src/css/curCSS.js
index 98a594a77..111285b2e 100644
--- a/src/css/curCSS.js
+++ b/src/css/curCSS.js
@@ -1,61 +1,28 @@
 define( [
 	"../core",
 	"../core/isAttached",
-	"./var/rboxStyle",
-	"./var/rnumnonpx",
-	"./var/getStyles",
-	"./support"
-], function( jQuery, isAttached, rboxStyle, rnumnonpx, getStyles, support ) {
+	"./var/getStyles"
+], function( jQuery, isAttached, rboxStyle, getStyles ) {
 
 "use strict";
 
 function curCSS( elem, name, computed ) {
-	var width, minWidth, maxWidth, ret,
-
-		// Support: Firefox 51+
-		// Retrieving style before computed somehow
-		// fixes an issue with getting wrong values
-		// on detached elements
-		style = elem.style;
+	var ret;
 
 	computed = computed || getStyles( elem );
 
-	// getPropertyValue is needed for:
-	//   .css('filter') (IE 9 only, #12537)
-	//   .css('--customProperty) (#3144)
+	// getPropertyValue is needed for `.css('--customProperty')` (gh-3144)
 	if ( computed ) {
 		ret = computed.getPropertyValue( name ) || computed[ name ];
 
 		if ( ret === "" && !isAttached( elem ) ) {
 			ret = jQuery.style( elem, name );
 		}
-
-		// A tribute to the "awesome hack by Dean Edwards"
-		// Android Browser returns percentage for some values,
-		// but width seems to be reliably pixels.
-		// This is against the CSSOM draft spec:
-		// https://drafts.csswg.org/cssom/#resolved-values
-		if ( !support.pixelBoxStyles() && rnumnonpx.test( ret ) && rboxStyle.test( name ) ) {
-
-			// Remember the original values
-			width = style.width;
-			minWidth = style.minWidth;
-			maxWidth = style.maxWidth;
-
-			// Put in the new values to get a computed value out
-			style.minWidth = style.maxWidth = style.width = ret;
-			ret = computed.width;
-
-			// Revert the changed values
-			style.width = width;
-			style.minWidth = minWidth;
-			style.maxWidth = maxWidth;
-		}
 	}
 
 	return ret !== undefined ?
 
-		// Support: IE <=9 - 11 only
+		// Support: IE <=9 - 11+
 		// IE returns zIndex value as an integer.
 		ret + "" :
 		ret;
diff --git a/src/css/support.js b/src/css/support.js
index 9c4da57d9..65763baec 100644
--- a/src/css/support.js
+++ b/src/css/support.js
@@ -9,58 +9,7 @@ define( [
 
 ( function() {
 
-	// Executing both pixelPosition & boxSizingReliable tests require only one layout
-	// so they're executed at the same time to save the second computation.
-	function computeStyleTests() {
-
-		// This is a singleton, we need to execute it only once
-		if ( !div ) {
-			return;
-		}
-
-		container.style.cssText = "position:absolute;left:-11111px;width:60px;" +
-			"margin-top:1px;padding:0;border:0";
-		div.style.cssText =
-			"position:relative;display:block;box-sizing:border-box;overflow:scroll;" +
-			"margin:auto;border:1px;padding:1px;" +
-			"width:60%;top:1%";
-		documentElement.appendChild( container ).appendChild( div );
-
-		var divStyle = window.getComputedStyle( div );
-		pixelPositionVal = divStyle.top !== "1%";
-
-		// Support: Android 4.0 - 4.3 only, Firefox <=3 - 44
-		reliableMarginLeftVal = roundPixelMeasures( divStyle.marginLeft ) === 12;
-
-		// Support: Android 4.0 - 4.3 only, Safari <=9.1 - 10.1, iOS <=7.0 - 9.3
-		// Some styles come back with percentage values, even though they shouldn't
-		div.style.right = "60%";
-		pixelBoxStylesVal = roundPixelMeasures( divStyle.right ) === 36;
-
-		// Support: IE 9 - 11 only
-		// Detect misreporting of content dimensions for box-sizing:border-box elements
-		boxSizingReliableVal = roundPixelMeasures( divStyle.width ) === 36;
-
-		// Support: IE 9 only
-		// Detect overflow:scroll screwiness (gh-3699)
-		// Support: Chrome <=64
-		// Don't get tricked when zoom affects offsetWidth (gh-4029)
-		div.style.position = "absolute";
-		scrollboxSizeVal = roundPixelMeasures( div.offsetWidth / 3 ) === 12;
-
-		documentElement.removeChild( container );
-
-		// Nullify the div so it wouldn't be stored in the memory and
-		// it will also be a sign that checks already performed
-		div = null;
-	}
-
-	function roundPixelMeasures( measure ) {
-		return Math.round( parseFloat( measure ) );
-	}
-
-	var pixelPositionVal, boxSizingReliableVal, scrollboxSizeVal, pixelBoxStylesVal,
-		reliableMarginLeftVal,
+	var boxSizingReliableVal,
 		container = document.createElement( "div" ),
 		div = document.createElement( "div" );
 
@@ -69,7 +18,7 @@ define( [
 		return;
 	}
 
-	// Support: IE <=9 - 11 only
+	// Support: IE <=9 - 11+
 	// Style of cloned element affects source element cloned (#8908)
 	div.style.backgroundClip = "content-box";
 	div.cloneNode( true ).style.backgroundClip = "";
@@ -77,24 +26,31 @@ define( [
 
 	jQuery.extend( support, {
 		boxSizingReliable: function() {
-			computeStyleTests();
+
+			// This is a singleton, we need to execute it only once
+			if ( div ) {
+				container.style.cssText = "position:absolute;left:-11111px;width:60px;" +
+					"margin-top:1px;padding:0;border:0";
+				div.style.cssText =
+					"position:relative;display:block;box-sizing:border-box;overflow:scroll;" +
+					"margin:auto;border:1px;padding:1px;" +
+					"width:60%;top:1%";
+				documentElement.appendChild( container ).appendChild( div );
+
+				var divStyle = window.getComputedStyle( div );
+
+				// Support: IE 9 - 11+
+				// Detect misreporting of content dimensions for box-sizing:border-box elements
+				boxSizingReliableVal = Math.round( parseFloat( divStyle.width ) ) === 36;
+
+				documentElement.removeChild( container );
+
+				// Nullify the div so it wouldn't be stored in the memory and
+				// it will also be a sign that checks already performed
+				div = null;
+			}
+
 			return boxSizingReliableVal;
-		},
-		pixelBoxStyles: function() {
-			computeStyleTests();
-			return pixelBoxStylesVal;
-		},
-		pixelPosition: function() {
-			computeStyleTests();
-			return pixelPositionVal;
-		},
-		reliableMarginLeft: function() {
-			computeStyleTests();
-			return reliableMarginLeftVal;
-		},
-		scrollboxSize: function() {
-			computeStyleTests();
-			return scrollboxSizeVal;
 		}
 	} );
 } )();
diff --git a/src/css/var/getStyles.js b/src/css/var/getStyles.js
index 0b893acf0..7adbdcfb5 100644
--- a/src/css/var/getStyles.js
+++ b/src/css/var/getStyles.js
@@ -3,12 +3,14 @@ define( function() {
 
 	return function( elem ) {
 
-		// Support: IE <=11 only, Firefox <=30 (#15098, #14150)
-		// IE throws on elements created in popups
-		// FF meanwhile throws on frame elements through "defaultView.getComputedStyle"
+		// Support: IE <=11+ (trac-14150)
+		// In IE popup's `window` is the opener window which makes `window.getComputedStyle( elem )`
+		// break. Using `elem.ownerDocument.defaultView` avoids the issue.
 		var view = elem.ownerDocument.defaultView;
 
-		if ( !view || !view.opener ) {
+		// `document.implementation.createHTMLDocument( "" )` has a `null` `defaultView`
+		// property; check `defaultView` truthiness to fallback to window in such a case.
+		if ( !view ) {
 			view = window;
 		}
 
diff --git a/src/css/var/isHiddenWithinTree.js b/src/css/var/isHiddenWithinTree.js
index 0ab610e29..1e99b96d3 100644
--- a/src/css/var/isHiddenWithinTree.js
+++ b/src/css/var/isHiddenWithinTree.js
@@ -1,9 +1,8 @@
 define( [
-	"../../core",
-	"../../core/isAttached"
+	"../../core"
 
 	// css is assumed
-], function( jQuery, isAttached ) {
+], function( jQuery ) {
 	"use strict";
 
 	// isHiddenWithinTree reports if an element has a non-"none" display style (inline and/or
@@ -22,13 +21,6 @@ define( [
 		// Inline style trumps all
 		return elem.style.display === "none" ||
 			elem.style.display === "" &&
-
-			// Otherwise, check computed style
-			// Support: Firefox <=43 - 45
-			// Disconnected elements can have computed display: none, so first confirm that elem is
-			// in the document.
-			isAttached( elem ) &&
-
 			jQuery.css( elem, "display" ) === "none";
 	};
 } );
diff --git a/src/data.js b/src/data.js
index 95c365a5a..d6706493a 100644
--- a/src/data.js
+++ b/src/data.js
@@ -108,7 +108,7 @@ jQuery.fn.extend( {
 					i = attrs.length;
 					while ( i-- ) {
 
-						// Support: IE 11 only
+						// Support: IE 11+
 						// The attrs elements can be null (#14894)
 						if ( attrs[ i ] ) {
 							name = attrs[ i ].name;
diff --git a/src/data/Data.js b/src/data/Data.js
index 31ff4318c..c94480fcd 100644
--- a/src/data/Data.js
+++ b/src/data/Data.js
@@ -141,7 +141,7 @@ Data.prototype = {
 		// Remove the expando if there's no more data
 		if ( key === undefined || jQuery.isEmptyObject( cache ) ) {
 
-			// Support: Chrome <=35 - 45
+			// Support: Chrome <=35 - 45+
 			// Webkit & Blink performance suffers when deleting properties
 			// from DOM nodes, so set to undefined instead
 			// https://bugs.chromium.org/p/chromium/issues/detail?id=378607 (bug restricted)
diff --git a/src/deferred.js b/src/deferred.js
index 0425d3631..81a1d0140 100644
--- a/src/deferred.js
+++ b/src/deferred.js
@@ -1,9 +1,8 @@
 define( [
 	"./core",
-	"./var/isFunction",
 	"./var/slice",
 	"./callbacks"
-], function( jQuery, isFunction, slice ) {
+], function( jQuery, slice ) {
 
 "use strict";
 
@@ -20,11 +19,11 @@ function adoptValue( value, resolve, reject, noValue ) {
 	try {
 
 		// Check for promise aspect first to privilege synchronous behavior
-		if ( value && isFunction( ( method = value.promise ) ) ) {
+		if ( value && typeof( method = value.promise ) === "function" ) {
 			method.call( value ).done( resolve ).fail( reject );
 
 		// Other thenables
-		} else if ( value && isFunction( ( method = value.then ) ) ) {
+		} else if ( value && typeof( method = value.then ) === "function" ) {
 			method.call( value, resolve, reject );
 
 		// Other non-thenables
@@ -40,10 +39,7 @@ function adoptValue( value, resolve, reject, noValue ) {
 	// Since jQuery.when doesn't unwrap thenables, we can skip the extra checks appearing in
 	// Deferred#then to conditionally suppress rejection.
 	} catch ( value ) {
-
-		// Support: Android 4.0 only
-		// Strict mode functions invoked without .call/.apply get global-object context
-		reject.apply( undefined, [ value ] );
+		reject( value );
 	}
 }
 
@@ -70,7 +66,7 @@ jQuery.extend( {
 					deferred.done( arguments ).fail( arguments );
 					return this;
 				},
-				"catch": function( fn ) {
+				catch: function( fn ) {
 					return promise.then( null, fn );
 				},
 
@@ -82,14 +78,15 @@ jQuery.extend( {
 						jQuery.each( tuples, function( i, tuple ) {
 
 							// Map tuples (progress, done, fail) to arguments (done, fail, progress)
-							var fn = isFunction( fns[ tuple[ 4 ] ] ) && fns[ tuple[ 4 ] ];
+							var fn = typeof fns[ tuple[ 4 ] ] === "function" &&
+								fns[ tuple[ 4 ] ];
 
 							// deferred.progress(function() { bind to newDefer or newDefer.notify })
 							// deferred.done(function() { bind to newDefer or newDefer.resolve })
 							// deferred.fail(function() { bind to newDefer or newDefer.reject })
 							deferred[ tuple[ 1 ] ]( function() {
 								var returned = fn && fn.apply( this, arguments );
-								if ( returned && isFunction( returned.promise ) ) {
+								if ( returned && typeof returned.promise === "function" ) {
 									returned.promise()
 										.progress( newDefer.notify )
 										.done( newDefer.resolve )
@@ -143,7 +140,7 @@ jQuery.extend( {
 										returned.then;
 
 									// Handle a returned thenable
-									if ( isFunction( then ) ) {
+									if ( typeof then === "function" ) {
 
 										// Special processors (notify) just wait for resolution
 										if ( special ) {
@@ -239,7 +236,7 @@ jQuery.extend( {
 							resolve(
 								0,
 								newDefer,
-								isFunction( onProgress ) ?
+								typeof onProgress === "function" ?
 									onProgress :
 									Identity,
 								newDefer.notifyWith
@@ -251,7 +248,7 @@ jQuery.extend( {
 							resolve(
 								0,
 								newDefer,
-								isFunction( onFulfilled ) ?
+								typeof onFulfilled === "function" ?
 									onFulfilled :
 									Identity
 							)
@@ -262,7 +259,7 @@ jQuery.extend( {
 							resolve(
 								0,
 								newDefer,
-								isFunction( onRejected ) ?
+								typeof onRejected === "function" ?
 									onRejected :
 									Thrower
 							)
@@ -380,7 +377,7 @@ jQuery.extend( {
 
 			// Use .then() to unwrap secondary thenables (cf. gh-3000)
 			if ( master.state() === "pending" ||
-				isFunction( resolveValues[ i ] && resolveValues[ i ].then ) ) {
+				typeof( resolveValues[ i ] && resolveValues[ i ].then ) === "function" ) {
 
 				return master.then();
 			}
diff --git a/src/deferred/exceptionHook.js b/src/deferred/exceptionHook.js
index 6dbdc8520..f6faf4123 100644
--- a/src/deferred/exceptionHook.js
+++ b/src/deferred/exceptionHook.js
@@ -11,10 +11,12 @@ var rerrorNames = /^(Eval|Internal|Range|Reference|Syntax|Type|URI)Error$/;
 
 jQuery.Deferred.exceptionHook = function( error, stack ) {
 
-	// Support: IE 8 - 9 only
-	// Console exists when dev tools are open, which can happen at any time
-	if ( window.console && window.console.warn && error && rerrorNames.test( error.name ) ) {
-		window.console.warn( "jQuery.Deferred exception: " + error.message, error.stack, stack );
+	if ( error && rerrorNames.test( error.name ) ) {
+		window.console.warn(
+			"jQuery.Deferred exception: " + error.message,
+			error.stack,
+			stack
+		);
 	}
 };
 
diff --git a/src/deprecated.js b/src/deprecated.js
index ecdf9f450..10d708ce2 100644
--- a/src/deprecated.js
+++ b/src/deprecated.js
@@ -3,12 +3,11 @@ define( [
 	"./core/nodeName",
 	"./core/toType",
 	"./css/cssCamelCase",
-	"./var/isFunction",
 	"./var/isWindow",
 	"./var/slice",
 
 	"./event/alias"
-], function( jQuery, nodeName, toType, cssCamelCase, isFunction, isWindow, slice ) {
+], function( jQuery, nodeName, toType, cssCamelCase, isWindow, slice ) {
 
 "use strict";
 
@@ -48,7 +47,7 @@ jQuery.proxy = function( fn, context ) {
 
 	// Quick check to determine if target is callable, in the spec
 	// this throws a TypeError, but we will just return undefined.
-	if ( !isFunction( fn ) ) {
+	if ( typeof fn !== "function" ) {
 		return undefined;
 	}
 
diff --git a/src/effects.js b/src/effects.js
index c9332f7d7..147aa065f 100644
--- a/src/effects.js
+++ b/src/effects.js
@@ -1,7 +1,6 @@
 define( [
 	"./core",
 	"./var/document",
-	"./var/isFunction",
 	"./var/rcssNum",
 	"./var/rnothtmlwhite",
 	"./css/var/cssExpand",
@@ -19,7 +18,7 @@ define( [
 	"./manipulation",
 	"./css",
 	"./effects/Tween"
-], function( jQuery, document, isFunction, rcssNum, rnothtmlwhite, cssExpand,
+], function( jQuery, document, rcssNum, rnothtmlwhite, cssExpand,
 	isHiddenWithinTree, swap, adjustCSS, cssCamelCase, dataPriv, showHide ) {
 
 "use strict";
@@ -150,7 +149,7 @@ function defaultPrefilter( elem, props, opts ) {
 	// Restrict "overflow" and "display" styles during box animations
 	if ( isBox && elem.nodeType === 1 ) {
 
-		// Support: IE <=9 - 11, Edge 12 - 15
+		// Support: IE <=9 - 11+, Edge 12 - 18+
 		// Record all 3 overflow attributes because IE does not infer the shorthand
 		// from identically-valued overflowX and overflowY and Edge just mirrors
 		// the overflowX value there.
@@ -310,10 +309,7 @@ function Animation( elem, properties, options ) {
 			var currentTime = fxNow || createFxNow(),
 				remaining = Math.max( 0, animation.startTime + animation.duration - currentTime ),
 
-				// Support: Android 2.3 only
-				// Archaic crash bug won't allow us to use `1 - ( 0.5 || 0 )` (#12497)
-				temp = remaining / animation.duration || 0,
-				percent = 1 - temp,
+				percent = 1 - ( remaining / animation.duration || 0 ),
 				index = 0,
 				length = animation.tweens.length;
 
@@ -386,7 +382,7 @@ function Animation( elem, properties, options ) {
 	for ( ; index < length; index++ ) {
 		result = Animation.prefilters[ index ].call( animation, elem, props, animation.opts );
 		if ( result ) {
-			if ( isFunction( result.stop ) ) {
+			if ( typeof result.stop === "function" ) {
 				jQuery._queueHooks( animation.elem, animation.opts.queue ).stop =
 					result.stop.bind( result );
 			}
@@ -396,7 +392,7 @@ function Animation( elem, properties, options ) {
 
 	jQuery.map( props, createTween, animation );
 
-	if ( isFunction( animation.opts.start ) ) {
+	if ( typeof animation.opts.start === "function" ) {
 		animation.opts.start.call( elem, animation );
 	}
 
@@ -429,7 +425,7 @@ jQuery.Animation = jQuery.extend( Animation, {
 	},
 
 	tweener: function( props, callback ) {
-		if ( isFunction( props ) ) {
+		if ( typeof props === "function" ) {
 			callback = props;
 			props = [ "*" ];
 		} else {
@@ -461,9 +457,9 @@ jQuery.Animation = jQuery.extend( Animation, {
 jQuery.speed = function( speed, easing, fn ) {
 	var opt = speed && typeof speed === "object" ? jQuery.extend( {}, speed ) : {
 		complete: fn || !fn && easing ||
-			isFunction( speed ) && speed,
+			typeof speed === "function" && speed,
 		duration: speed,
-		easing: fn && easing || easing && !isFunction( easing ) && easing
+		easing: fn && easing || easing && typeof easing !== "function" && easing
 	};
 
 	// Go to the end state if fx are off
@@ -490,7 +486,7 @@ jQuery.speed = function( speed, easing, fn ) {
 	opt.old = opt.complete;
 
 	opt.complete = function() {
-		if ( isFunction( opt.old ) ) {
+		if ( typeof opt.old === "function" ) {
 			opt.old.call( this );
 		}
 
diff --git a/src/effects/Tween.js b/src/effects/Tween.js
index f8c847f97..0c5fe67d3 100644
--- a/src/effects/Tween.js
+++ b/src/effects/Tween.js
@@ -98,16 +98,6 @@ Tween.propHooks = {
 	}
 };
 
-// Support: IE <=9 only
-// Panic based approach to setting things on disconnected nodes
-Tween.propHooks.scrollTop = Tween.propHooks.scrollLeft = {
-	set: function( tween ) {
-		if ( tween.elem.nodeType && tween.elem.parentNode ) {
-			tween.elem[ tween.prop ] = tween.now;
-		}
-	}
-};
-
 jQuery.easing = {
 	linear: function( p ) {
 		return p;
diff --git a/src/event.js b/src/event.js
index 3ff11ad0b..405d176a0 100644
--- a/src/event.js
+++ b/src/event.js
@@ -2,7 +2,6 @@ define( [
 	"./core",
 	"./var/document",
 	"./var/documentElement",
-	"./var/isFunction",
 	"./var/rnothtmlwhite",
 	"./var/rcheckableType",
 	"./var/slice",
@@ -11,7 +10,7 @@ define( [
 
 	"./core/init",
 	"./selector"
-], function( jQuery, document, documentElement, isFunction, rnothtmlwhite,
+], function( jQuery, document, documentElement, rnothtmlwhite,
 	rcheckableType, slice, dataPriv, nodeName ) {
 
 "use strict";
@@ -36,16 +35,7 @@ function returnFalse() {
 // (focus and blur are always synchronous in other supported browsers,
 // this just defines when we can count on it).
 function expectSync( elem, type ) {
-	return ( elem === safeActiveElement() ) === ( type === "focus" );
-}
-
-// Support: IE <=9 only
-// Accessing document.activeElement can throw unexpectedly
-// https://bugs.jquery.com/ticket/13393
-function safeActiveElement() {
-	try {
-		return document.activeElement;
-	} catch ( err ) { }
+	return ( elem === document.activeElement ) === ( type === "focus" );
 }
 
 function on( elem, types, selector, data, fn, one ) {
@@ -379,14 +369,10 @@ jQuery.event = {
 		// Find delegate handlers
 		if ( delegateCount &&
 
-			// Support: IE <=9
-			// Black-hole SVG <use> instance trees (trac-13180)
-			cur.nodeType &&
-
-			// Support: Firefox <=42
+			// Support: Firefox <=42 - 66+
 			// Suppress spec-violating clicks indicating a non-primary pointer button (trac-3861)
 			// https://www.w3.org/TR/DOM-Level-3-Events/#event-type-click
-			// Support: IE 11 only
+			// Support: IE 11+
 			// ...but not arrow key "clicks" of radio inputs, which can have `button` -1 (gh-2343)
 			!( event.type === "click" && event.button >= 1 ) ) {
 
@@ -433,7 +419,7 @@ jQuery.event = {
 			enumerable: true,
 			configurable: true,
 
-			get: isFunction( hook ) ?
+			get: typeof hook === "function" ?
 				function() {
 					if ( this.originalEvent ) {
 							return hook( this.originalEvent );
@@ -519,8 +505,9 @@ jQuery.event = {
 		beforeunload: {
 			postDispatch: function( event ) {
 
-				// Support: Firefox 20+
-				// Firefox doesn't alert if the returnValue field is not set.
+				// Support: Chrome <=73+
+				// Chrome doesn't alert on `event.preventDefault()`
+				// as the standard mandates.
 				if ( event.result !== undefined && event.originalEvent ) {
 					event.originalEvent.returnValue = event.result;
 				}
@@ -638,21 +625,12 @@ jQuery.Event = function( src, props ) {
 
 		// Events bubbling up the document may have been marked as prevented
 		// by a handler lower down the tree; reflect the correct value.
-		this.isDefaultPrevented = src.defaultPrevented ||
-				src.defaultPrevented === undefined &&
-
-				// Support: Android <=2.3 only
-				src.returnValue === false ?
+		this.isDefaultPrevented = src.defaultPrevented ?
 			returnTrue :
 			returnFalse;
 
 		// Create target properties
-		// Support: Safari <=6 - 7 only
-		// Target should not be a text node (#504, #13143)
-		this.target = ( src.target && src.target.nodeType === 3 ) ?
-			src.target.parentNode :
-			src.target;
-
+		this.target = src.target;
 		this.currentTarget = src.currentTarget;
 		this.relatedTarget = src.relatedTarget;
 
@@ -805,11 +783,6 @@ jQuery.each( { focus: "focusin", blur: "focusout" }, function( type, delegateTyp
 // Create mouseenter/leave events using mouseover/out and event-time checks
 // so that event delegation works in jQuery.
 // Do the same for pointerenter/pointerleave and pointerover/pointerout
-//
-// Support: Safari 7 only
-// Safari sends mouseenter too often; see:
-// https://bugs.chromium.org/p/chromium/issues/detail?id=470258
-// for the description of the bug (it existed in older Chrome versions as well).
 jQuery.each( {
 	mouseenter: "mouseover",
 	mouseleave: "mouseout",
diff --git a/src/event/trigger.js b/src/event/trigger.js
index cf40b4faa..39f641b70 100644
--- a/src/event/trigger.js
+++ b/src/event/trigger.js
@@ -4,10 +4,9 @@ define( [
 	"../data/var/dataPriv",
 	"../data/var/acceptData",
 	"../var/hasOwn",
-	"../var/isFunction",
 	"../var/isWindow",
 	"../event"
-], function( jQuery, document, dataPriv, acceptData, hasOwn, isFunction, isWindow ) {
+], function( jQuery, document, dataPriv, acceptData, hasOwn, isWindow ) {
 
 "use strict";
 
@@ -129,7 +128,7 @@ jQuery.extend( jQuery.event, {
 
 				// Call a native DOM method on the target with the same name as the event.
 				// Don't do default actions on window, that's where global variables be (#6170)
-				if ( ontype && isFunction( elem[ type ] ) && !isWindow( elem ) ) {
+				if ( ontype && typeof elem[ type ] === "function" && !isWindow( elem ) ) {
 
 					// Don't re-trigger an onFOO event when we call its FOO() method
 					tmp = elem[ ontype ];
diff --git a/src/manipulation.js b/src/manipulation.js
index ab19d8b3c..fb10ef5c2 100644
--- a/src/manipulation.js
+++ b/src/manipulation.js
@@ -2,7 +2,6 @@ define( [
 	"./core",
 	"./core/isAttached",
 	"./var/concat",
-	"./var/isFunction",
 	"./var/push",
 	"./var/rcheckableType",
 	"./core/access",
@@ -24,7 +23,7 @@ define( [
 	"./traversing",
 	"./selector",
 	"./event"
-], function( jQuery, isAttached, concat, isFunction, push, rcheckableType,
+], function( jQuery, isAttached, concat, push, rcheckableType,
 	access, rtagName, rscriptType,
 	wrapMap, getAll, setGlobalEval, buildFragment, support,
 	dataPriv, dataUser, acceptData, DOMEval, nodeName ) {
@@ -40,13 +39,11 @@ var
 
 	/* eslint-enable */
 
-	// Support: IE <=10 - 11, Edge 12 - 13 only
+	// Support: IE <=10 - 11+, Edge 12 - 13 only
 	// In IE/Edge using regex groups here causes severe slowdowns.
 	// See https://connect.microsoft.com/IE/feedback/details/1736512/
 	rnoInnerhtml = /<script|<style|<link/i,
 
-	// checked="checked" or checked
-	rchecked = /checked\s*(?:[^=]|=\s*.checked.)/i,
 	rcleanScript = /^\s*<!(?:\[CDATA\[|--)|(?:\]\]|--)>\s*$/g;
 
 // Prefer a tbody over its parent table for containing new rows
@@ -109,20 +106,6 @@ function cloneCopyEvent( src, dest ) {
 	}
 }
 
-// Fix IE bugs, see support tests
-function fixInput( src, dest ) {
-	var nodeName = dest.nodeName.toLowerCase();
-
-	// Fails to persist the checked state of a cloned checkbox or radio button.
-	if ( nodeName === "input" && rcheckableType.test( src.type ) ) {
-		dest.checked = src.checked;
-
-	// Fails to return the selected option to the default selected state when cloning options
-	} else if ( nodeName === "input" || nodeName === "textarea" ) {
-		dest.defaultValue = src.defaultValue;
-	}
-}
-
 function domManip( collection, args, callback, ignored ) {
 
 	// Flatten any nested arrays
@@ -133,17 +116,12 @@ function domManip( collection, args, callback, ignored ) {
 		l = collection.length,
 		iNoClone = l - 1,
 		value = args[ 0 ],
-		valueIsFunction = isFunction( value );
+		valueIsFunction = typeof value === "function";
 
-	// We can't cloneNode fragments that contain checked, in WebKit
-	if ( valueIsFunction ||
-			( l > 1 && typeof value === "string" &&
-				!support.checkClone && rchecked.test( value ) ) ) {
+	if ( valueIsFunction ) {
 		return collection.each( function( index ) {
 			var self = collection.eq( index );
-			if ( valueIsFunction ) {
-				args[ 0 ] = value.call( this, index, self.html() );
-			}
+			args[ 0 ] = value.call( this, index, self.html() );
 			domManip( self, args, callback, ignored );
 		} );
 	}
@@ -172,9 +150,6 @@ function domManip( collection, args, callback, ignored ) {
 
 					// Keep references to cloned scripts for later restoration
 					if ( hasScripts ) {
-
-						// Support: Android <=4.0 only, PhantomJS 1 only
-						// push.apply(_, arraylike) throws on ancient WebKit
 						jQuery.merge( scripts, getAll( node, "script" ) );
 					}
 				}
@@ -255,7 +230,13 @@ jQuery.extend( {
 			srcElements = getAll( elem );
 
 			for ( i = 0, l = srcElements.length; i < l; i++ ) {
-				fixInput( srcElements[ i ], destElements[ i ] );
+
+				// Support: IE <=11+
+				// IE fails to set the defaultValue to the correct value when
+				// cloning other types of input fields
+				if ( destElements[ i ].nodeName.toLowerCase() === "textarea" ) {
+					destElements[ i ].defaultValue = srcElements[ i ].defaultValue;
+				}
 			}
 		}
 
@@ -475,9 +456,6 @@ jQuery.each( {
 		for ( ; i <= last; i++ ) {
 			elems = i === last ? this : this.clone( true );
 			jQuery( insert[ i ] )[ original ]( elems );
-
-			// Support: Android <=4.0 only, PhantomJS 1 only
-			// .get() because push.apply(_, arraylike) throws on ancient WebKit
 			push.apply( ret, elems.get() );
 		}
 
diff --git a/src/manipulation/buildFragment.js b/src/manipulation/buildFragment.js
index 40c2ed1dc..01dcff6e5 100644
--- a/src/manipulation/buildFragment.js
+++ b/src/manipulation/buildFragment.js
@@ -27,9 +27,6 @@ function buildFragment( elems, context, scripts, selection, ignored ) {
 
 			// Add nodes directly
 			if ( toType( elem ) === "object" ) {
-
-				// Support: Android <=4.0 only, PhantomJS 1 only
-				// push.apply(_, arraylike) throws on ancient WebKit
 				jQuery.merge( nodes, elem.nodeType ? [ elem ] : elem );
 
 			// Convert non-html into a text node
@@ -51,8 +48,6 @@ function buildFragment( elems, context, scripts, selection, ignored ) {
 					tmp = tmp.lastChild;
 				}
 
-				// Support: Android <=4.0 only, PhantomJS 1 only
-				// push.apply(_, arraylike) throws on ancient WebKit
 				jQuery.merge( nodes, tmp.childNodes );
 
 				// Remember the top-level container
diff --git a/src/manipulation/getAll.js b/src/manipulation/getAll.js
index fede6c78a..89634d694 100644
--- a/src/manipulation/getAll.js
+++ b/src/manipulation/getAll.js
@@ -7,7 +7,7 @@ define( [
 
 function getAll( context, tag ) {
 
-	// Support: IE <=9 - 11 only
+	// Support: IE <=9 - 11+
 	// Use typeof to avoid zero-argument method invocation on host objects (#15151)
 	var ret;
 
diff --git a/src/manipulation/support.js b/src/manipulation/support.js
index 4a5d9af4c..f2ff88e17 100644
--- a/src/manipulation/support.js
+++ b/src/manipulation/support.js
@@ -10,21 +10,14 @@ define( [
 		div = fragment.appendChild( document.createElement( "div" ) ),
 		input = document.createElement( "input" );
 
-	// Support: Android 4.0 - 4.3 only
-	// Check state lost if the name is set (#11217)
 	// Support: Windows Web Apps (WWA)
 	// `name` and `type` must use .setAttribute for WWA (#14901)
 	input.setAttribute( "type", "radio" );
 	input.setAttribute( "checked", "checked" );
-	input.setAttribute( "name", "t" );
 
 	div.appendChild( input );
 
-	// Support: Android <=4.1 only
-	// Older WebKit doesn't clone checked state correctly in fragments
-	support.checkClone = div.cloneNode( true ).cloneNode( true ).lastChild.checked;
-
-	// Support: IE <=11 only
+	// Support: IE <=11+
 	// Make sure textarea (and checkbox) defaultValue is properly cloned
 	div.innerHTML = "<textarea>x</textarea>";
 	support.noCloneChecked = !!div.cloneNode( true ).lastChild.defaultValue;
diff --git a/src/manipulation/wrapMap.js b/src/manipulation/wrapMap.js
index 1f446f7d7..065225928 100644
--- a/src/manipulation/wrapMap.js
+++ b/src/manipulation/wrapMap.js
@@ -5,11 +5,10 @@ define( function() {
 // We have to close these tags to support XHTML (#13200)
 var wrapMap = {
 
-	// Support: IE <=9 only
-	option: [ 1, "<select multiple='multiple'>", "</select>" ],
-
+	// Table parts need to be wrapped with `<table>` or they're
+	// stripped to their contents when put in a div.
 	// XHTML parsers do not magically insert elements in the
-	// same way that tag soup parsers do. So we cannot shorten
+	// same way that tag soup parsers do, so we cannot shorten
 	// this by omitting <tbody> or other required elements.
 	thead: [ 1, "<table>", "</table>" ],
 	col: [ 2, "<table><colgroup>", "</colgroup></table>" ],
@@ -19,9 +18,6 @@ var wrapMap = {
 	_default: [ 0, "", "" ]
 };
 
-// Support: IE <=9 only
-wrapMap.optgroup = wrapMap.option;
-
 wrapMap.tbody = wrapMap.tfoot = wrapMap.colgroup = wrapMap.caption = wrapMap.thead;
 wrapMap.th = wrapMap.td;
 
diff --git a/src/offset.js b/src/offset.js
index 83b1c3a53..531b75ff2 100644
--- a/src/offset.js
+++ b/src/offset.js
@@ -3,17 +3,13 @@ define( [
 	"./core/access",
 	"./var/document",
 	"./var/documentElement",
-	"./var/isFunction",
 	"./css/var/rnumnonpx",
 	"./css/curCSS",
-	"./css/addGetHookIf",
-	"./css/support",
 	"./var/isWindow",
 	"./core/init",
 	"./css",
 	"./selector" // contains
-], function( jQuery, access, document, documentElement, isFunction, rnumnonpx,
-             curCSS, addGetHookIf, support, isWindow ) {
+], function( jQuery, access, document, documentElement, rnumnonpx, curCSS, isWindow ) {
 
 "use strict";
 
@@ -47,7 +43,7 @@ jQuery.offset = {
 			curLeft = parseFloat( curCSSLeft ) || 0;
 		}
 
-		if ( isFunction( options ) ) {
+		if ( typeof options === "function" ) {
 
 			// Use jQuery.extend here to allow modification of coordinates argument (gh-1848)
 			options = options.call( elem, i, jQuery.extend( {}, curOffset ) );
@@ -91,7 +87,7 @@ jQuery.fn.extend( {
 		}
 
 		// Return zeros for disconnected and hidden (display: none) elements (gh-2310)
-		// Support: IE <=11 only
+		// Support: IE <=11+
 		// Running getBoundingClientRect on a
 		// disconnected node in IE throws an error
 		if ( !elem.getClientRects().length ) {
@@ -208,26 +204,5 @@ jQuery.each( { scrollLeft: "pageXOffset", scrollTop: "pageYOffset" }, function(
 	};
 } );
 
-// Support: Safari <=7 - 9.1, Chrome <=37 - 49
-// Add the top/left cssHooks using jQuery.fn.position
-// Webkit bug: https://bugs.webkit.org/show_bug.cgi?id=29084
-// Blink bug: https://bugs.chromium.org/p/chromium/issues/detail?id=589347
-// getComputedStyle returns percent when specified for top/left/bottom/right;
-// rather than make the css module depend on the offset module, just check for it here
-jQuery.each( [ "top", "left" ], function( i, prop ) {
-	jQuery.cssHooks[ prop ] = addGetHookIf( support.pixelPosition,
-		function( elem, computed ) {
-			if ( computed ) {
-				computed = curCSS( elem, prop );
-
-				// If curCSS returns percentage, fallback to offset
-				return rnumnonpx.test( computed ) ?
-					jQuery( elem ).position()[ prop ] + "px" :
-					computed;
-			}
-		}
-	);
-} );
-
 return jQuery;
 } );
diff --git a/src/selector-native.js b/src/selector-native.js
index da837a004..20c37f4fa 100644
--- a/src/selector-native.js
+++ b/src/selector-native.js
@@ -35,11 +35,10 @@ define( [
 
 var hasDuplicate, sortInput,
 	sortStable = jQuery.expando.split( "" ).sort( sortOrder ).join( "" ) === jQuery.expando,
-	matches = documentElement.matches ||
-		documentElement.webkitMatchesSelector ||
-		documentElement.mozMatchesSelector ||
-		documentElement.oMatchesSelector ||
-		documentElement.msMatchesSelector,
+
+	// Support: IE 9 - 11+
+	// IE requires a prefix.
+	matches = documentElement.matches || documentElement.msMatchesSelector,
 
 	// CSS string/identifier serialization
 	// https://drafts.csswg.org/cssom/#common-serializing-idioms
diff --git a/src/selector-sizzle.js b/src/selector-sizzle.js
index ff7bc70ee..1a30d7ded 100644
--- a/src/selector-sizzle.js
+++ b/src/selector-sizzle.js
@@ -10,6 +10,7 @@ jQuery.expr = Sizzle.selectors;
 
 // Deprecated
 jQuery.expr[ ":" ] = jQuery.expr.pseudos;
+
 jQuery.uniqueSort = jQuery.unique = Sizzle.uniqueSort;
 jQuery.text = Sizzle.getText;
 jQuery.isXMLDoc = Sizzle.isXML;
diff --git a/src/serialize.js b/src/serialize.js
index d8a9a36a4..0cf5ddb44 100644
--- a/src/serialize.js
+++ b/src/serialize.js
@@ -2,11 +2,10 @@ define( [
 	"./core",
 	"./core/toType",
 	"./var/rcheckableType",
-	"./var/isFunction",
 	"./core/init",
 	"./traversing", // filter
 	"./attributes/prop"
-], function( jQuery, toType, rcheckableType, isFunction ) {
+], function( jQuery, toType, rcheckableType ) {
 
 "use strict";
 
@@ -62,7 +61,7 @@ jQuery.param = function( a, traditional ) {
 		add = function( key, valueOrFunction ) {
 
 			// If value is a function, invoke it and use its return value
-			var value = isFunction( valueOrFunction ) ?
+			var value = typeof valueOrFunction === "function" ?
 				valueOrFunction() :
 				valueOrFunction;
 
diff --git a/src/traversing.js b/src/traversing.js
index 426d5b6ea..18b964a49 100644
--- a/src/traversing.js
+++ b/src/traversing.js
@@ -149,7 +149,7 @@ jQuery.each( {
 			return elem.contentDocument;
 		}
 
-		// Support: IE 9 - 11 only, iOS 7 only, Android Browser <=4.3 only
+		// Support: IE 9 - 11+
 		// Treat the template element as a regular one in browsers that
 		// don't support it.
 		if ( nodeName( elem, "template" ) ) {
diff --git a/src/traversing/findFilter.js b/src/traversing/findFilter.js
index 268dad796..2f526b713 100644
--- a/src/traversing/findFilter.js
+++ b/src/traversing/findFilter.js
@@ -1,16 +1,15 @@
 define( [
 	"../core",
 	"../var/indexOf",
-	"../var/isFunction",
 	"./var/rneedsContext",
 	"../selector"
-], function( jQuery, indexOf, isFunction, rneedsContext ) {
+], function( jQuery, indexOf, rneedsContext ) {
 
 "use strict";
 
 // Implement the identical functionality for filter and not
 function winnow( elements, qualifier, not ) {
-	if ( isFunction( qualifier ) ) {
+	if ( typeof qualifier === "function" ) {
 		return jQuery.grep( elements, function( elem, i ) {
 			return !!qualifier.call( elem, i, elem ) !== not;
 		} );
diff --git a/src/var/isFunction.js b/src/var/isFunction.js
deleted file mode 100644
index dad662e4f..000000000
--- a/src/var/isFunction.js
+++ /dev/null
@@ -1,13 +0,0 @@
-define( function() {
-	"use strict";
-
-	return function isFunction( obj ) {
-
-      // Support: Chrome <=57, Firefox <=52
-      // In some browsers, typeof returns "function" for HTML <object> elements
-      // (i.e., `typeof document.createElement( "object" ) === "function"`).
-      // We don't want to classify *any* DOM node as a function.
-      return typeof obj === "function" && typeof obj.nodeType !== "number";
-  };
-
-} );
diff --git a/src/var/trim.js b/src/var/trim.js
new file mode 100644
index 000000000..a5e75af36
--- /dev/null
+++ b/src/var/trim.js
@@ -0,0 +1,5 @@
+define( function() {
+	"use strict";
+
+	return "".trim;
+} );
diff --git a/src/wrap.js b/src/wrap.js
index 41b716f9f..a42c04da7 100644
--- a/src/wrap.js
+++ b/src/wrap.js
@@ -1,10 +1,9 @@
 define( [
 	"./core",
-	"./var/isFunction",
 	"./core/init",
 	"./manipulation", // clone
 	"./traversing" // parent, contents
-], function( jQuery, isFunction ) {
+], function( jQuery ) {
 
 "use strict";
 
@@ -13,7 +12,7 @@ jQuery.fn.extend( {
 		var wrap;
 
 		if ( this[ 0 ] ) {
-			if ( isFunction( html ) ) {
+			if ( typeof html === "function" ) {
 				html = html.call( this[ 0 ] );
 			}
 
@@ -39,7 +38,7 @@ jQuery.fn.extend( {
 	},
 
 	wrapInner: function( html ) {
-		if ( isFunction( html ) ) {
+		if ( typeof html === "function" ) {
 			return this.each( function( i ) {
 				jQuery( this ).wrapInner( html.call( this, i ) );
 			} );
@@ -59,7 +58,7 @@ jQuery.fn.extend( {
 	},
 
 	wrap: function( html ) {
-		var htmlIsFunction = isFunction( html );
+		var htmlIsFunction = typeof html === "function";
 
 		return this.each( function( i ) {
 			jQuery( this ).wrapAll( htmlIsFunction ? html.call( this, i ) : html );
diff --git a/src/wrapper.js b/src/wrapper.js
index 0af1f4964..7af4ad75e 100644
--- a/src/wrapper.js
+++ b/src/wrapper.js
@@ -40,10 +40,6 @@
 // Pass this if window is not defined yet
 } )( typeof window !== "undefined" ? window : this, function( window, noGlobal ) {
 
-// Edge <= 12 - 13+, Firefox <=18 - 45+, IE 10 - 11, Safari 5.1 - 9+, iOS 6 - 9.1
-// throw exceptions when non-strict code (e.g., ASP.NET 4.5) accesses strict mode
-// arguments.callee.caller (trac-13335). But as of jQuery 3.0 (2016), strict mode should be common
-// enough that all such attempts are guarded in a try block.
 "use strict";
 
 // @CODE
diff --git a/test/data/core/cc_on.html b/test/data/core/cc_on.html
deleted file mode 100644
index 5db18916c..000000000
--- a/test/data/core/cc_on.html
+++ /dev/null
@@ -1,23 +0,0 @@
-<!DOCTYPE html>
-<html lang="en">
-<head>
-	<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
-	<script>
-		var cc_on = false,
-			errors = [];
-/*@cc_on
-		cc_on = true;
-@*/
-		window.onerror = function( errorMessage, filePath, lineNumber ) {
-			errors.push( errorMessage );
-		};
-	</script>
-	<script src="../../jquery.js"></script>
-	<script src="../iframeTest.js"></script>
-</head>
-<body>
-	<script>
-		startIframeTest( cc_on, errors );
-	</script>
-</body>
-</html>
diff --git a/test/data/testinit.js b/test/data/testinit.js
index e1d81c5c7..eb4901062 100644
--- a/test/data/testinit.js
+++ b/test/data/testinit.js
@@ -1,5 +1,7 @@
 /* eslint no-multi-str: "off" */
 
+"use strict";
+
 var FILEPATH = "/test/data/testinit.js",
 	activeScript = [].slice.call( document.getElementsByTagName( "script" ), -1 )[ 0 ],
 	parentUrl = activeScript && activeScript.src ?
@@ -100,43 +102,9 @@ this.createDashboardXML = function() {
 	return jQuery.parseXML( string );
 };
 
-this.createWithFriesXML = function() {
-	var string = "<?xml version='1.0' encoding='UTF-8'?> \
-	<soap:Envelope xmlns:soap='http://schemas.xmlsoap.org/soap/envelope/' \
-		xmlns:xsd='http://www.w3.org/2001/XMLSchema' \
-		xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'> \
-		<soap:Body> \
-			<jsconf xmlns='http://{{ externalHost }}/ns1'> \
-				<response xmlns:ab='http://{{ externalHost }}/ns2'> \
-					<meta> \
-						<component id='seite1' class='component'> \
-							<properties xmlns:cd='http://{{ externalHost }}/ns3'> \
-								<property name='prop1'> \
-									<thing /> \
-									<value>1</value> \
-								</property> \
-								<property name='prop2'> \
-									<thing att='something' /> \
-								</property> \
-								<foo_bar>foo</foo_bar> \
-							</properties> \
-						</component> \
-					</meta> \
-				</response> \
-			</jsconf> \
-		</soap:Body> \
-	</soap:Envelope>";
-
-	return jQuery.parseXML( string.replace( /\{\{\s*externalHost\s*\}\}/g, externalHost ) );
-};
-
 this.createXMLFragment = function() {
-	var xml, frag;
-	if ( window.ActiveXObject ) {
-		xml = new window.ActiveXObject( "msxml2.domdocument" );
-	} else {
+	var frag,
 		xml = document.implementation.createDocument( "", "", null );
-	}
 
 	if ( xml ) {
 		frag = xml.createElement( "data" );
@@ -314,10 +282,9 @@ this.loadTests = function() {
 	require( [ parentUrl + "test/data/testrunner.js" ], function() {
 		var i = 0,
 			tests = [
-				// A special module with basic tests, meant for
-				// not fully supported environments like Android 2.3,
-				// jsdom or PhantomJS. We run it everywhere, though,
-				// to make sure tests are not broken.
+				// A special module with basic tests, meant for not fully
+				// supported environments like jsdom. We run it everywhere,
+				// though, to make sure tests are not broken.
 				"unit/basic.js",
 
 				"unit/core.js",
@@ -351,7 +318,6 @@ this.loadTests = function() {
 				if ( !QUnit.basicTests || i === 1 ) {
 					require( [ parentUrl + "test/" + dep ], loadDep );
 
-				// Support: Android 2.3 only
 				// When running basic tests, replace other modules with dummies to avoid overloading
 				// impaired clients.
 				} else {
diff --git a/test/data/testrunner.js b/test/data/testrunner.js
index 39000c33b..c4fa5d378 100644
--- a/test/data/testrunner.js
+++ b/test/data/testrunner.js
@@ -1,5 +1,7 @@
 ( function() {
 
+"use strict";
+
 // Store the old counts so that we only assert on tests that have actually leaked,
 // instead of asserting every time a test has leaked sometime in the past
 var oldCacheLength = 0,
diff --git a/test/unit/ajax.js b/test/unit/ajax.js
index 7bf3f686b..9b151988d 100644
--- a/test/unit/ajax.js
+++ b/test/unit/ajax.js
@@ -120,9 +120,7 @@ QUnit.module( "ajax", {
 				assert.ok( true, "success" );
 			},
 			fail: function() {
-				if ( jQuery.support.cors === false ) {
-					assert.ok( true, "fail" );
-				}
+				assert.ok( false, "fail" );
 			},
 			complete: function() {
 				assert.ok( true, "complete" );
@@ -269,13 +267,12 @@ QUnit.module( "ajax", {
 				"Nullable": null,
 				"undefined": undefined
 
-				// Support: IE 9 - 11, Edge 12 - 14 only
+				// Support: IE 9 - 11+, Edge 12 - 14 only
 				// Not all browsers allow empty-string headers
 				//"Empty": ""
 			},
 			success: function( data, _, xhr ) {
 				var i, emptyHeader,
-					isAndroid = /android 4\.[0-3]/i.test( navigator.userAgent ),
 					requestHeaders = jQuery.extend( this.headers, {
 						"ajax-send": "test"
 					} ),
@@ -296,25 +293,8 @@ QUnit.module( "ajax", {
 					assert.strictEqual( emptyHeader, "", "Empty header received" );
 				}
 				assert.strictEqual( xhr.getResponseHeader( "Sample-Header2" ), "Hello World 2", "Second sample header received" );
-
-				if ( isAndroid ) {
-					// Support: Android 4.0-4.3 only
-					// Android Browser only returns the last value for each header
-					// so there's no way for jQuery get all parts.
-					assert.ok( true, "Android doesn't support repeated header names" );
-				} else {
-					assert.strictEqual( xhr.getResponseHeader( "List-Header" ), "Item 1, Item 2", "List header received" );
-				}
-
-				if ( isAndroid && QUnit.isSwarm ) {
-					// Support: Android 4.0-4.3 on BrowserStack only
-					// Android Browser versions provided by BrowserStack fail this test
-					// while locally fired emulators don't, even when they connect
-					// to TestSwarm. Just skip the test there to avoid a red build.
-					assert.ok( true, "BrowserStack's Android fails the \"prototype collision (constructor)\" test" );
-				} else {
-					assert.strictEqual( xhr.getResponseHeader( "constructor" ), "prototype collision (constructor)", "constructor header received" );
-				}
+				assert.strictEqual( xhr.getResponseHeader( "List-Header" ), "Item 1, Item 2", "List header received" );
+				assert.strictEqual( xhr.getResponseHeader( "constructor" ), "prototype collision (constructor)", "constructor header received" );
 				assert.strictEqual( xhr.getResponseHeader( "__proto__" ), null, "Undefined __proto__ header not received" );
 			}
 		};
@@ -553,47 +533,41 @@ QUnit.module( "ajax", {
 		};
 	} );
 
-	if ( !/android 4\.0/i.test( navigator.userAgent ) ) {
-		ajaxTest( "jQuery.ajax() - native abort", 2, function( assert ) {
-			return {
-				url: url( "mock.php?action=wait&wait=1" ),
-				xhr: function() {
-					var xhr = new window.XMLHttpRequest();
-					setTimeout( function() {
-						xhr.abort();
-					}, 100 );
-					return xhr;
-				},
-				error: function( xhr, msg ) {
-					assert.strictEqual( msg, "error", "Native abort triggers error callback" );
-				},
-				complete: function() {
-					assert.ok( true, "complete" );
-				}
-			};
-		} );
-	}
+	ajaxTest( "jQuery.ajax() - native abort", 2, function( assert ) {
+		return {
+			url: url( "mock.php?action=wait&wait=1" ),
+			xhr: function() {
+				var xhr = new window.XMLHttpRequest();
+				setTimeout( function() {
+					xhr.abort();
+				}, 100 );
+				return xhr;
+			},
+			error: function( xhr, msg ) {
+				assert.strictEqual( msg, "error", "Native abort triggers error callback" );
+			},
+			complete: function() {
+				assert.ok( true, "complete" );
+			}
+		};
+	} );
 
-	// Support: Android <= 4.0 - 4.3 only
-	// Android 4.0-4.3 does not have ontimeout on an xhr
-	if ( "ontimeout" in new window.XMLHttpRequest() ) {
-		ajaxTest( "jQuery.ajax() - native timeout", 2, function( assert ) {
-			return {
-				url: url( "mock.php?action=wait&wait=1" ),
-				xhr: function() {
-					var xhr = new window.XMLHttpRequest();
-					xhr.timeout = 1;
-					return xhr;
-				},
-				error: function( xhr, msg ) {
-					assert.strictEqual( msg, "error", "Native timeout triggers error callback" );
-				},
-				complete: function() {
-					assert.ok( true, "complete" );
-				}
-			};
-		} );
-	}
+	ajaxTest( "jQuery.ajax() - native timeout", 2, function( assert ) {
+		return {
+			url: url( "mock.php?action=wait&wait=1" ),
+			xhr: function() {
+				var xhr = new window.XMLHttpRequest();
+				xhr.timeout = 1;
+				return xhr;
+			},
+			error: function( xhr, msg ) {
+				assert.strictEqual( msg, "error", "Native timeout triggers error callback" );
+			},
+			complete: function() {
+				assert.ok( true, "complete" );
+			}
+		};
+	} );
 
 	ajaxTest( "jQuery.ajax() - events with context", 12, function( assert ) {
 		var context = document.createElement( "div" );
diff --git a/test/unit/basic.js b/test/unit/basic.js
index bed27dcba..8b567f195 100644
--- a/test/unit/basic.js
+++ b/test/unit/basic.js
@@ -179,7 +179,11 @@ QUnit.test( "manipulation", function( assert ) {
 		".html getter/setter"
 	);
 
-	assert.strictEqual( elem1.append( elem2 )[ 0 ].childNodes[ 1 ], elem2[ 0 ], ".append" );
+	assert.strictEqual(
+		elem1.append( elem2 )[ 0 ].childNodes[ elem1[ 0 ].childNodes.length - 1 ],
+		elem2[ 0 ],
+		".append"
+	);
 	assert.strictEqual( elem1.prepend( elem2 )[ 0 ].childNodes[ 0 ], elem2[ 0 ], ".prepend" );
 
 	child = elem1.find( "span" );
diff --git a/test/unit/core.js b/test/unit/core.js
index 3cb2d3951..6c331349a 100644
--- a/test/unit/core.js
+++ b/test/unit/core.js
@@ -1319,22 +1319,20 @@ QUnit.test( "jQuery.parseHTML(<a href>) - gh-2965", function( assert ) {
 	assert.ok( /\/example\.html$/.test( href ), "href is not lost after parsing anchor" );
 } );
 
-if ( jQuery.support.createHTMLDocument ) {
-	QUnit.test( "jQuery.parseHTML", function( assert ) {
-		var done = assert.async();
-		assert.expect( 1 );
+QUnit.test( "jQuery.parseHTML", function( assert ) {
+	var done = assert.async();
+	assert.expect( 1 );
 
-		Globals.register( "parseHTMLError" );
+	Globals.register( "parseHTMLError" );
 
-		jQuery.globalEval( "parseHTMLError = false;" );
-		jQuery.parseHTML( "<img src=x onerror='parseHTMLError = true'>" );
+	jQuery.globalEval( "parseHTMLError = false;" );
+	jQuery.parseHTML( "<img src=x onerror='parseHTMLError = true'>" );
 
-		window.setTimeout( function() {
-			assert.equal( window.parseHTMLError, false, "onerror eventhandler has not been called." );
-			done();
-		}, 2000 );
-	} );
-}
+	window.setTimeout( function() {
+		assert.equal( window.parseHTMLError, false, "onerror eventhandler has not been called." );
+		done();
+	}, 2000 );
+} );
 
 QUnit.test( "jQuery.parseXML", function( assert ) {
 	assert.expect( 8 );
@@ -1371,30 +1369,14 @@ QUnit.test( "jQuery.parseXML", function( assert ) {
 } );
 
 testIframe(
-	"Conditional compilation compatibility (#13274)",
-	"core/cc_on.html",
-	function( assert, jQuery, window, document, cc_on, errors ) {
-		assert.expect( 3 );
-		assert.ok( true, "JScript conditional compilation " + ( cc_on ? "supported" : "not supported" ) );
-		assert.deepEqual( errors, [], "No errors" );
-		assert.ok( jQuery(), "jQuery executes" );
+	"document ready when jQuery loaded asynchronously (#13655)",
+	"core/dynamic_ready.html",
+	function( assert, jQuery, window, document, ready ) {
+		assert.expect( 1 );
+		assert.equal( true, ready, "document ready correctly fired when jQuery is loaded after DOMContentLoaded" );
 	}
 );
 
-// iOS7 doesn't fire the load event if the long-loading iframe gets its source reset to about:blank.
-// This makes this test fail but it doesn't seem to cause any real-life problems so blacklisting
-// this test there is preferred to complicating the hard-to-test core/ready code further.
-if ( !/iphone os 7_/i.test( navigator.userAgent ) ) {
-	testIframe(
-		"document ready when jQuery loaded asynchronously (#13655)",
-		"core/dynamic_ready.html",
-		function( assert, jQuery, window, document, ready ) {
-			assert.expect( 1 );
-			assert.equal( true, ready, "document ready correctly fired when jQuery is loaded after DOMContentLoaded" );
-		}
-	);
-}
-
 testIframe(
 	"Tolerating alias-masked DOM properties (#14074)",
 	"core/aliased.html",
diff --git a/test/unit/css.js b/test/unit/css.js
index 74daa2b2d..75b1cc7ef 100644
--- a/test/unit/css.js
+++ b/test/unit/css.js
@@ -641,7 +641,7 @@ QUnit.test( "show/hide detached nodes", function( assert ) {
 	span.remove();
 } );
 
-QUnit[ document.body.attachShadow ? "test" : "skip" ]( "show/hide shadow child nodes", function( assert ) {
+QUnit[ document.body.getRootNode ? "test" : "skip" ]( "show/hide shadow child nodes", function( assert ) {
 	assert.expect( 28 );
 	jQuery( "<div id='shadowHost'></div>" ).appendTo( "#qunit-fixture" );
 	var shadowHost = document.querySelector( "#shadowHost" );
@@ -1023,7 +1023,7 @@ QUnit[ jQuery.find.compile && jQuery.fn.toggle ? "test" : "skip" ]( "detached to
 		"cascade-hidden element in detached tree" );
 } );
 
-QUnit[ jQuery.find.compile && jQuery.fn.toggle && document.body.attachShadow ? "test" : "skip" ]( "shadow toggle()", function( assert ) {
+QUnit[ jQuery.find.compile && jQuery.fn.toggle && document.body.getRootNode ? "test" : "skip" ]( "shadow toggle()", function( assert ) {
 	assert.expect( 4 );
 	jQuery( "<div id='shadowHost'></div>" ).appendTo( "#qunit-fixture" );
 	var shadowHost = document.querySelector( "#shadowHost" );
@@ -1420,16 +1420,6 @@ QUnit.test( "certain css values of 'normal' should be convertable to a number, s
 	assert.equal( typeof el.css( "fontWeight" ), "string", ".css() returns a string" );
 } );
 
-// Support: IE 9 only
-// Only run this test in IE9
-if ( document.documentMode === 9 ) {
-	QUnit.test( ".css('filter') returns a string in IE9, see #12537", function( assert ) {
-		assert.expect( 1 );
-
-		assert.equal( jQuery( "<div style='-ms-filter:\"progid:DXImageTransform.Microsoft.gradient(startColorstr=#FFFFFF, endColorstr=#ECECEC)\";'></div>" ).css( "filter" ), "progid:DXImageTransform.Microsoft.gradient(startColorstr=#FFFFFF, endColorstr=#ECECEC)", "IE9 returns the correct value from css('filter')." );
-	} );
-}
-
 QUnit.test( "cssHooks - expand", function( assert ) {
 	assert.expect( 15 );
 	var result,
@@ -1489,9 +1479,9 @@ QUnit.test( "css opacity consistency across browsers (#12685)", function( assert
 } );
 
 QUnit[ jQuery.find.compile ? "test" : "skip" ]( ":visible/:hidden selectors", function( assert ) {
-	assert.expect( 17 );
+	assert.expect( 18 );
 
-	var $div, $table, $a;
+	var $div, $table, $a, $br;
 
 	assert.ok( jQuery( "#nothiddendiv" ).is( ":visible" ), "Modifying CSS display: Assert element is visible" );
 	jQuery( "#nothiddendiv" ).css( { display: "none" } );
@@ -1513,10 +1503,8 @@ QUnit[ jQuery.find.compile ? "test" : "skip" ]( ":visible/:hidden selectors", fu
 	$div.css( { width: 0, height: 0, overflow: "hidden" } );
 	assert.ok( $div.is( ":visible" ), "Div with width and height of 0 is still visible (gh-2227)" );
 
-	// Safari 6-7 and iOS 6-7 report 0 width for br elements
-	// When newer browsers propagate, re-enable this test
-	// $br = jQuery( "<br/>" ).appendTo( "#qunit-fixture" );
-	// assert.ok( $br.is( ":visible" ), "br element is visible" );
+	$br = jQuery( "<br/>" ).appendTo( "#qunit-fixture" );
+	assert.ok( $br.is( ":visible" ), "br element is visible" );
 
 	$table = jQuery( "#table" );
 	$table.html( "<tr><td style='display:none'>cell</td><td>cell</td></tr>" );
@@ -1539,11 +1527,7 @@ QUnit.test( "Keep the last style if the new one isn't recognized by the browser
 	assert.equal( el.css( "position" ), "absolute", "The old style is kept when setting an unrecognized value" );
 } );
 
-// Support: Edge 14 - 16 only
-// Edge collapses whitespace-only values when setting a style property and
-// there is no easy way for us to work around it. Just skip the test there
-// and hope for the better future.
-QUnit[ /\bedge\/16\./i.test( navigator.userAgent ) ? "skip" : "test" ](
+QUnit.test(
 	"Keep the last style if the new one is a non-empty whitespace (gh-3204)",
 	function( assert ) {
 	assert.expect( 1 );
@@ -1648,25 +1632,14 @@ QUnit.test(
 	}
 );
 
-// Support: IE <=10 only
-// We have to jump through the hoops here in order to test work with "order" CSS property,
-// that some browsers do not support. This test is not, strictly speaking, correct,
-// but it's the best that we can do.
-( function() {
-	var style = document.createElement( "div" ).style,
-		exist = "order" in style || "WebkitOrder" in style;
-
-	if ( exist ) {
-		QUnit.test( "Don't append px to CSS \"order\" value (#14049)", function( assert ) {
-			assert.expect( 1 );
+QUnit.test( "Don't append px to CSS \"order\" value (#14049)", function( assert ) {
+	assert.expect( 1 );
 
-			var $elem = jQuery( "<div/>" );
+	var $elem = jQuery( "<div/>" );
 
-			$elem.css( "order", 2 );
-			assert.equal( $elem.css( "order" ), "2", "2 on order" );
-		} );
-	}
-} )();
+	$elem.css( "order", 2 );
+	assert.equal( $elem.css( "order" ), "2", "2 on order" );
+} );
 
 QUnit.test( "Do not throw on frame elements from css method (#15098)", function( assert ) {
 	assert.expect( 1 );
@@ -1788,18 +1761,12 @@ QUnit.test( "Do not throw on frame elements from css method (#15098)", function(
 		var div = jQuery( "<div>" ).appendTo( "#qunit-fixture" ),
 			$elem = jQuery( "<div>" ).addClass( "test__customProperties" )
 				.appendTo( "#qunit-fixture" ),
-			webkit = /\bsafari\b/i.test( navigator.userAgent ) &&
-				!/\firefox\b/i.test( navigator.userAgent ) &&
-				!/\edge\b/i.test( navigator.userAgent ),
-			oldSafari = webkit && ( /\b9\.\d(\.\d+)* safari/i.test( navigator.userAgent ) ||
-				/\b10\.0(\.\d+)* safari/i.test( navigator.userAgent ) ||
-				/iphone os (?:9|10)_/i.test( navigator.userAgent ) ),
+			webkitOrBlink = /\bsafari\b/i.test( navigator.userAgent ) &&
+				!/\bfirefox\b/i.test( navigator.userAgent ) &&
+				!/\bedge\b/i.test( navigator.userAgent ),
 			expected = 10;
 
-		if ( webkit ) {
-			expected -= 2;
-		}
-		if ( oldSafari ) {
+		if ( webkitOrBlink ) {
 			expected -= 2;
 		}
 		assert.expect( expected );
@@ -1825,17 +1792,13 @@ QUnit.test( "Do not throw on frame elements from css method (#15098)", function(
 
 		assert.equal( $elem.css( "--prop1" ), "val1", "Basic CSS custom property" );
 
-		// Support: Safari 9.1-10.0 only
-		// Safari collapses whitespaces & quotes. Ignore it.
-		if ( !oldSafari ) {
-			assert.equal( $elem.css( "--prop2" ), " val2", "Preceding whitespace maintained" );
-			assert.equal( $elem.css( "--prop3" ), "val3 ", "Following whitespace maintained" );
-		}
+		assert.equal( $elem.css( "--prop2" ), " val2", "Preceding whitespace maintained" );
+		assert.equal( $elem.css( "--prop3" ), "val3 ", "Following whitespace maintained" );
 
-		// Support: Chrome 49-55, Safari 9.1-10.0
+		// Support: Chrome <=49 - 73+, Safari <=9.1 - 12.1+
 		// Chrome treats single quotes as double ones.
 		// Safari treats double quotes as single ones.
-		if ( !webkit ) {
+		if ( !webkitOrBlink ) {
 			assert.equal( $elem.css( "--prop4" ), "\"val4\"", "Works with double quotes" );
 			assert.equal( $elem.css( "--prop5" ), "'val5'", "Works with single quotes" );
 		}
diff --git a/test/unit/deferred.js b/test/unit/deferred.js
index c704f905f..936a57524 100644
--- a/test/unit/deferred.js
+++ b/test/unit/deferred.js
@@ -172,7 +172,7 @@ QUnit.test( "jQuery.Deferred.catch", function( assert ) {
 
 	var value1, value2, value3,
 		defer = jQuery.Deferred(),
-		piped = defer[ "catch" ]( function( a, b ) {
+		piped = defer.catch( function( a, b ) {
 			return a * b;
 		} ),
 		done = jQuery.map( new Array( 3 ), function() { return assert.async(); } );
@@ -186,18 +186,18 @@ QUnit.test( "jQuery.Deferred.catch", function( assert ) {
 		value2 = b;
 	} );
 
-	defer.reject( 2, 3 )[ "catch" ]( function() {
+	defer.reject( 2, 3 ).catch( function() {
 		assert.strictEqual( value1, 2, "first reject value ok" );
 		assert.strictEqual( value2, 3, "second reject value ok" );
 		assert.strictEqual( value3, 6, "result of filter ok" );
 		done.pop().call();
 	} );
 
-	jQuery.Deferred().resolve()[ "catch" ]( function() {
+	jQuery.Deferred().resolve().catch( function() {
 		assert.ok( false, "then should not be called on resolve" );
 	} ).then( done.pop() );
 
-	jQuery.Deferred().reject()[ "catch" ]( jQuery.noop ).done( function( value ) {
+	jQuery.Deferred().reject().catch( jQuery.noop ).done( function( value ) {
 		assert.strictEqual( value, undefined, "then fail callback can return undefined/null" );
 		done.pop().call();
 	} );
@@ -563,8 +563,7 @@ QUnit[ typeof Symbol === "function" && Symbol.toStringTag ? "test" : "skip" ](
 	}
 );
 
-// Test fails in IE9 but is skipped there because console is not active
-QUnit[ window.console ? "test" : "skip" ]( "jQuery.Deferred.exceptionHook", function( assert ) {
+QUnit.test( "jQuery.Deferred.exceptionHook", function( assert ) {
 
 	assert.expect( 2 );
 
@@ -573,24 +572,10 @@ QUnit[ window.console ? "test" : "skip" ]( "jQuery.Deferred.exceptionHook", func
 		oldWarn = window.console.warn;
 
 	window.console.warn = function() {
-
-		// Support: Chrome <=41 only
-		// Some Chrome versions newer than 30 but older than 42 display the "undefined is
-		// not a function" error, not mentioning the function name. This has been fixed
-		// in Chrome 42. Relax this test there.
-		// This affects our Android 5.0 & Yandex.Browser testing.
-		var msg = Array.prototype.join.call( arguments, " " ),
-			oldChromium = false;
-		if ( /chrome/i.test( navigator.userAgent ) ) {
-			oldChromium = parseInt(
-					navigator.userAgent.match( /chrome\/(\d+)/i )[ 1 ], 10 ) < 42;
-		}
-		if ( oldChromium ) {
-			assert.ok( /(?:barf|undefined)/.test( msg ), "Message (weak assertion): " + msg );
-		} else {
-			assert.ok( /barf/.test( msg ), "Message: " + msg );
-		}
+		var msg = Array.prototype.join.call( arguments, " " );
+		assert.ok( /barf/.test( msg ), "Message: " + msg );
 	};
+
 	jQuery.when(
 		defer.then( function() {
 
@@ -613,8 +598,7 @@ QUnit[ window.console ? "test" : "skip" ]( "jQuery.Deferred.exceptionHook", func
 	defer.resolve();
 } );
 
-// Test fails in IE9 but is skipped there because console is not active
-QUnit[ window.console ? "test" : "skip" ]( "jQuery.Deferred.exceptionHook with stack hooks", function( assert ) {
+QUnit.test( "jQuery.Deferred.exceptionHook with stack hooks", function( assert ) {
 
 	assert.expect( 2 );
 
@@ -632,26 +616,11 @@ QUnit[ window.console ? "test" : "skip" ]( "jQuery.Deferred.exceptionHook with s
 	};
 
 	window.console.warn = function() {
-
-		// Support: Chrome <=41 only
-		// Some Chrome versions newer than 30 but older than 42 display the "undefined is
-		// not a function" error, not mentioning the function name. This has been fixed
-		// in Chrome 42. Relax this test there.
-		// This affects our Android 5.0 & Yandex.Browser testing.
-		var msg = Array.prototype.join.call( arguments, " " ),
-			oldChromium = false;
-		if ( /chrome/i.test( navigator.userAgent ) ) {
-			oldChromium = parseInt(
-					navigator.userAgent.match( /chrome\/(\d+)/i )[ 1 ], 10 ) < 42;
-		}
-		if ( oldChromium ) {
-			assert.ok( /(?:cough_up_hairball|undefined)/.test( msg ),
-				"Function mentioned (weak assertion): " + msg );
-		} else {
-			assert.ok( /cough_up_hairball/.test( msg ), "Function mentioned: " + msg );
-		}
+		var msg = Array.prototype.join.call( arguments, " " );
+		assert.ok( /cough_up_hairball/.test( msg ), "Function mentioned: " + msg );
 		assert.ok( /NO STACK FOR YOU/.test( msg ), "Stack trace included: " + msg );
 	};
+
 	defer.then( function() {
 		jQuery.cough_up_hairball();
 	} ).then( null, function( ) {
@@ -825,11 +794,7 @@ QUnit.test( "jQuery.when(nonThenable) - like Promise.resolve", function( assert
 
 	assert.expect( 44 );
 
-	var
-
-		// Support: Android 4.0 only
-		// Strict mode functions invoked without .call/.apply get global-object context
-		defaultContext = ( function getDefaultContext() { return this; } ).call(),
+	var defaultContext = ( function getDefaultContext() { return this; } )(),
 
 		done = assert.async( 20 );
 
@@ -884,9 +849,7 @@ QUnit.test( "jQuery.when(thenable) - like Promise.resolve", function( assert ) {
 
 	var customToStringThen = {
 		then: function( onFulfilled ) {
-			// Support: Android 4.0 only
-			// Strict mode functions invoked without .call/.apply get global-object context
-			onFulfilled.call();
+			onFulfilled();
 		}
 	};
 	if ( typeof Symbol === "function" ) {
@@ -947,9 +910,7 @@ QUnit.test( "jQuery.when(thenable) - like Promise.resolve", function( assert ) {
 		},
 		numCases = Object.keys( willSucceed ).length + Object.keys( willError ).length,
 
-		// Support: Android 4.0 only
-		// Strict mode functions invoked without .call/.apply get global-object context
-		defaultContext = ( function getDefaultContext() { return this; } ).call(),
+		defaultContext = ( function getDefaultContext() { return this; } )(),
 
 		done = assert.async( numCases * 2 );
 
@@ -1027,9 +988,7 @@ QUnit.test( "jQuery.when(a, b) - like Promise.all", function( assert ) {
 			rejectedStandardPromise: true
 		},
 
-		// Support: Android 4.0 only
-		// Strict mode functions invoked without .call/.apply get global-object context
-		defaultContext = ( function getDefaultContext() { return this; } ).call(),
+		defaultContext = ( function getDefaultContext() { return this; } )(),
 
 		done = assert.async( 98 );
 
diff --git a/test/unit/dimensions.js b/test/unit/dimensions.js
index 23a58523c..4a3ad5ecb 100644
--- a/test/unit/dimensions.js
+++ b/test/unit/dimensions.js
@@ -687,19 +687,7 @@ QUnit.test( "interaction with scrollbars (gh-3589)", function( assert ) {
 			.css( { position: "relative" } ),
 		$boxes = jQuery(
 			[ plainBox[ 0 ], contentBox[ 0 ], borderBox[ 0 ], relativeBorderBox[ 0 ] ]
-		).appendTo( parent ),
-
-		// Support: IE 9 only
-		// Computed width seems to report content width even with "box-sizing: border-box", and
-		// "overflow: scroll" actually _shrinks_ the element (gh-3699).
-		borderBoxLoss =
-			borderBox.clone().css( { overflow: "auto" } ).appendTo( parent )[ 0 ].offsetWidth -
-			borderBox[ 0 ].offsetWidth;
-
-	if ( borderBoxLoss > 0 ) {
-		borderBox[ 0 ].style.width = ( size + borderBoxLoss ) + "px";
-		borderBox[ 0 ].style.height = ( size + borderBoxLoss ) + "px";
-	}
+		).appendTo( parent );
 
 	for ( i = 0; i < 3; i++ ) {
 		if ( i === 1 ) {
@@ -758,10 +746,9 @@ QUnit.test( "outerWidth/Height for table cells and textarea with border-box in I
 		$secondTh = jQuery( "<th style='width: 190px;padding: 5px' />" ),
 		$thirdTh = jQuery( "<th style='width: 180px;padding: 5px' />" ),
 
-		// Support: Firefox 63, Edge 16-17, Android 8, iOS 7-11
-		// These browsers completely ignore the border-box and height settings
-		// The computed height is instead just line-height + border
-		// Either way, what we're doing in css.js is correct
+		// Most browsers completely ignore the border-box and height settings.
+		// The computed height is instead just line-height + border.
+		// Either way, what we're doing in css.js is correct.
 		$td = jQuery( "<td style='height: 20px;padding: 5px;border: 1px solid;line-height:18px'>text</td>" ),
 
 		$tbody = jQuery( "<tbody />" ).appendTo( $table ),
@@ -775,18 +762,7 @@ QUnit.test( "outerWidth/Height for table cells and textarea with border-box in I
 	assert.strictEqual( $firstTh.outerWidth(), 200, "First th has outerWidth 200." );
 	assert.strictEqual( $secondTh.outerWidth(), 200, "Second th has outerWidth 200." );
 	assert.strictEqual( $thirdTh.outerWidth(), 200, "Third th has outerWidth 200." );
-
-	// Support: Android 4.0-4.3 only
-	// Android Browser disregards td's box-sizing, treating it like it was content-box.
-	// Unlike in IE, offsetHeight shares the same issue so there's no easy way to workaround
-	// the issue without incurring high size penalty. Let's at least check we get the size
-	// as the browser sees it.
-	if ( /android 4\.[0-3]/i.test( navigator.userAgent ) ) {
-		assert.ok( [ 30, 32 ].indexOf( $td.outerHeight() ) > -1,
-			"outerHeight of td with border-box should include padding." );
-	} else {
-		assert.strictEqual( $td.outerHeight(), 30, "outerHeight of td with border-box should include padding." );
-	}
+	assert.strictEqual( $td.outerHeight(), 30, "outerHeight of td with border-box should include padding." );
 	assert.strictEqual( $textarea.outerHeight(), 6, "outerHeight of textarea with border-box should include padding and border." );
 } );
 
diff --git a/test/unit/effects.js b/test/unit/effects.js
index 05fd1283e..9f9f34514 100644
--- a/test/unit/effects.js
+++ b/test/unit/effects.js
@@ -221,7 +221,7 @@ supportjQuery.each( hideOptions, function( type, setup ) {
 		assert.expectJqData( this, $span, "olddisplay" );
 	} );
 
-	QUnit[ document.body.attachShadow ? "test" : "skip" ](
+	QUnit[ document.body.getRootNode ? "test" : "skip" ](
 		"Persist correct display value - " + type + " hidden, shadow child", function( assert ) {
 		assert.expect( 3 );
 
@@ -690,44 +690,35 @@ QUnit.test( "stop()", function( assert ) {
 	this.clock.tick( 100 );
 } );
 
-// In IE9 inside testswarm this test doesn't work properly
-( function() {
-	var type = "test";
-
-	if ( QUnit.isSwarm && /msie 9\.0/i.test( window.navigator.userAgent ) ) {
-		type = "skip";
-	}
-
-	QUnit[ type ]( "stop() - several in queue", function( assert ) {
-		assert.expect( 5 );
+QUnit.test( "stop() - several in queue", function( assert ) {
+	assert.expect( 5 );
 
-		var nw, $foo = jQuery( "#foo" );
+	var nw, $foo = jQuery( "#foo" );
 
-		// default duration is 400ms, so 800px ensures we aren't 0 or 1 after 1ms
-		$foo.hide().css( "width", 800 );
+	// default duration is 400ms, so 800px ensures we aren't 0 or 1 after 1ms
+	$foo.hide().css( "width", 800 );
 
-		$foo.animate( { "width": "show" }, 400, "linear" );
-		$foo.animate( { "width": "hide" } );
-		$foo.animate( { "width": "show" } );
+	$foo.animate( { "width": "show" }, 400, "linear" );
+	$foo.animate( { "width": "hide" } );
+	$foo.animate( { "width": "show" } );
 
-		this.clock.tick( 1 );
+	this.clock.tick( 1 );
 
-		jQuery.fx.tick();
-		assert.equal( $foo.queue().length, 3, "3 in the queue" );
+	jQuery.fx.tick();
+	assert.equal( $foo.queue().length, 3, "3 in the queue" );
 
-		nw = $foo.css( "width" );
-		assert.notEqual( parseFloat( nw ), 1, "An animation occurred " + nw );
-		$foo.stop();
+	nw = $foo.css( "width" );
+	assert.notEqual( parseFloat( nw ), 1, "An animation occurred " + nw );
+	$foo.stop();
 
-		assert.equal( $foo.queue().length, 2, "2 in the queue" );
-		nw = $foo.css( "width" );
-		assert.notEqual( parseFloat( nw ), 1, "Stop didn't reset the animation " + nw );
+	assert.equal( $foo.queue().length, 2, "2 in the queue" );
+	nw = $foo.css( "width" );
+	assert.notEqual( parseFloat( nw ), 1, "Stop didn't reset the animation " + nw );
 
-		$foo.stop( true );
+	$foo.stop( true );
 
-		assert.equal( $foo.queue().length, 0, "0 in the queue" );
-	} );
-} )();
+	assert.equal( $foo.queue().length, 0, "0 in the queue" );
+} );
 
 QUnit.test( "stop(clearQueue)", function( assert ) {
 	assert.expect( 4 );
diff --git a/test/unit/event.js b/test/unit/event.js
index b77da465e..756c8838b 100644
--- a/test/unit/event.js
+++ b/test/unit/event.js
@@ -1414,7 +1414,7 @@ QUnit.test( "Submit event can be stopped (#11049)", function( assert ) {
 	form.remove();
 } );
 
-// Support: iOS 7 - 9
+// Support: iOS <=7 - 12+
 // iOS has the window.onbeforeunload field but doesn't support the beforeunload
 // handler making it impossible to feature-detect the support.
 QUnit[ /(ipad|iphone|ipod)/i.test( navigator.userAgent ) ? "skip" : "test" ](
@@ -2434,7 +2434,7 @@ QUnit.test( "event object properties on natively-triggered event", function( ass
 		$link = jQuery( link ),
 		evt = document.createEvent( "MouseEvents" );
 
-	// Support: IE <=9 - 11 only
+	// Support: IE <=9 - 11+
 	// IE requires element to be in the body before it will dispatch
 	$link.appendTo( "body" ).on( "click", function( e ) {
 
@@ -2931,21 +2931,6 @@ QUnit.test( "trigger('click') on radio passes extra params", function( assert )
 	$radio.trigger( "click", [ true ] );
 } );
 
-// Support: IE <=9 only
-// https://msdn.microsoft.com/en-us/library/hh801223(v=vs.85).aspx
-QUnit.test( "VML with special event handlers (trac-7071)", function( assert ) {
-	assert.expect( 1 );
-
-	var ns = jQuery( "<xml:namespace ns='urn:schemas-microsoft-com:vml' prefix='v' />" ).appendTo( "head" );
-
-	jQuery( "<v:oval id='oval' style='width:100pt;height:75pt;' fillcolor='red'> </v:oval>" ).appendTo( "#form" );
-	jQuery( "#form" ).on( "keydown", function() {
-		assert.ok( true, "no error was thrown" );
-	} );
-	jQuery( "#oval" ).trigger( "click" ).trigger( "keydown" );
-	ns.remove();
-} );
-
 QUnit.test( "focusout/focusin support", function( assert ) {
 	assert.expect( 6 );
 
diff --git a/test/unit/manipulation.js b/test/unit/manipulation.js
index b0d3e3a88..e5cf856ec 100644
--- a/test/unit/manipulation.js
+++ b/test/unit/manipulation.js
@@ -511,18 +511,6 @@ QUnit.test( "Tag name processing respects the HTML Standard (gh-2005)", function
 	}
 
 	function assertSpecialCharsSupport( method, characters ) {
-		// Support: Android 4.4 only
-		// Chromium < 35 incorrectly upper-cases µ; Android 4.4 uses such a version by default
-		// (and its WebView, being un-updatable, will use it for eternity) so we need to blacklist
-		// that one for the tests to pass.
-		if ( characters === "µ" && /chrome/i.test( navigator.userAgent ) &&
-			navigator.userAgent.match( /chrome\/(\d+)/i )[ 1 ] < 35 ) {
-			assert.ok( true, "This Chromium version upper-cases µ incorrectly; skip test" );
-			assert.ok( true, "This Chromium version upper-cases µ incorrectly; skip test" );
-			assert.ok( true, "This Chromium version upper-cases µ incorrectly; skip test" );
-			return;
-		}
-
 		var child,
 			codepoint = characters.charCodeAt( 0 ).toString( 16 ).toUpperCase(),
 			description = characters.length === 1 ?
@@ -592,28 +580,7 @@ QUnit.test( "append(xml)", function( assert ) {
 	var xmlDoc, xml1, xml2;
 
 	function createXMLDoc() {
-
-		// Initialize DOM based upon latest installed MSXML or Netscape
-		var elem, n, len,
-			aActiveX =
-				[ "MSXML6.DomDocument",
-				"MSXML3.DomDocument",
-				"MSXML2.DomDocument",
-				"MSXML.DomDocument",
-				"Microsoft.XmlDom" ];
-
-		if ( document.implementation && "createDocument" in document.implementation ) {
-			return document.implementation.createDocument( "", "", null );
-		} else {
-
-			// IE
-			for ( n = 0, len = aActiveX.length; n < len; n++ ) {
-				try {
-					elem = new window.ActiveXObject( aActiveX[ n ] );
-					return elem;
-				} catch ( _ ) {}
-			}
-		}
+		return document.implementation.createDocument( "", "", null );
 	}
 
 	xmlDoc = createXMLDoc();
@@ -1798,7 +1765,7 @@ QUnit.test( "html(Function)", function( assert ) {
 } );
 
 QUnit[
-	// Support: Edge 16-18+
+	// Support: Edge 16 - 18+
 	// Edge sometimes doesn't execute module scripts so skip the test there.
 	( QUnit.moduleTypeSupported && !/edge\//i.test( navigator.userAgent ) ) ?
 		"test" :
@@ -1825,15 +1792,10 @@ QUnit[
 	}, 1000 );
 } );
 
-QUnit[
-	// Support: IE 9-11 only, Android 4.0-4.4 only, iOS 7-10 only
+QUnit.test( "html(script nomodule)", function( assert ) {
+
+	// Support: IE 9 - 11+
 	// `nomodule` scripts should be executed by legacy browsers only.
-	// iOS 10 supports `<script type="module">` but doesn't support the nomodule attribute
-	// so let's skip it here; sites supporting it must handle `nomodule` in a custom way anyway.
-	!/iphone os 10_/i.test( navigator.userAgent ) ?
-		"test" :
-		"skip"
-]( "html(script nomodule)", function( assert ) {
 	assert.expect( QUnit.moduleTypeSupported ? 0 : 4 );
 	var done = assert.async(),
 		$fixture = jQuery( "#qunit-fixture" );
@@ -2676,14 +2638,18 @@ QUnit.test( "Make sure specific elements with content created correctly (#13232)
 
 	jQuery.each( elems, function( name, value ) {
 		var html = "<" + name + ">" + value + "</" + name + ">";
-		assert.ok( jQuery.parseHTML( "<" + name + ">" + value + "</" + name + ">" )[ 0 ].nodeName.toLowerCase() === name, name + " is created correctly" );
+		assert.strictEqual(
+			jQuery.parseHTML( "<" + name + ">" + value + "</" + name + ">" )[ 0 ].nodeName.toLowerCase(),
+			name,
+			name + " is created correctly"
+		);
 
 		results.push( name );
 		args.push( html );
 	} );
 
 	jQuery.fn.append.apply( jQuery( "<div/>" ), args ).children().each( function( i ) {
-		assert.ok( this.nodeName.toLowerCase() === results[ i ] );
+		assert.strictEqual( this.nodeName.toLowerCase(), results[ i ] );
 	} );
 } );
 
@@ -2827,6 +2793,7 @@ QUnit.test( "Make sure tags with single-character names are found (gh-4124)", fu
 
 QUnit.test( "Insert script with data-URI (gh-1887)", function( assert ) {
 	assert.expect( 1 );
+
 	Globals.register( "testFoo" );
 	Globals.register( "testSrcFoo" );
 
@@ -2885,36 +2852,30 @@ testIframe(
 		} );
 	},
 
-	// Support: Edge 18+, iOS 7-9 only, Android 4.0-4.4 only
+	// Support: Edge <=18+
 	// Edge doesn't support nonce in non-inline scripts.
 	// See https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/13246371/
-	// Old iOS & Android Browser versions support script-src but not nonce, making this test
-	// impossible to run. Browsers not supporting CSP at all are not a problem as they'll skip
-	// script-src restrictions completely.
-	QUnit[ /\bedge\/|iphone os [789]|android 4\./i.test( navigator.userAgent ) ? "skip" : "test" ]
+	QUnit[ /\bedge\//i.test( navigator.userAgent ) ? "skip" : "test" ]
 );
 
 testIframe(
-    "Check if CSP nonce is preserved for external scripts with src attribute",
-    "mock.php?action=cspNonce&test=external",
-    function( assert, jQuery, window, document ) {
-        var done = assert.async();
-
-        assert.expect( 1 );
-
-        supportjQuery.get( baseURL + "support/csp.log" ).done( function( data ) {
-            assert.equal( data, "", "No log request should be sent" );
-            supportjQuery.get( baseURL + "mock.php?action=cspClean" ).done( done );
-        } );
-    },
-
-    // Support: Edge 18+, iOS 7-9 only, Android 4.0-4.4 only
-    // Edge doesn't support nonce in non-inline scripts.
-    // See https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/13246371/
-    // Old iOS & Android Browser versions support script-src but not nonce, making this test
-    // impossible to run. Browsers not supporting CSP at all are not a problem as they'll skip
-    // script-src restrictions completely.
-    QUnit[ /\bedge\/|iphone os [789]|android 4\./i.test( navigator.userAgent ) ? "skip" : "test" ]
+	"Check if CSP nonce is preserved for external scripts with src attribute",
+	"mock.php?action=cspNonce&test=external",
+	function( assert, jQuery, window, document ) {
+		var done = assert.async();
+
+		assert.expect( 1 );
+
+		supportjQuery.get( baseURL + "support/csp.log" ).done( function( data ) {
+			assert.equal( data, "", "No log request should be sent" );
+			supportjQuery.get( baseURL + "mock.php?action=cspClean" ).done( done );
+		} );
+	},
+
+	// Support: Edge <=18+
+	// Edge doesn't support nonce in non-inline scripts.
+	// See https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/13246371/
+	QUnit[ /\bedge\//i.test( navigator.userAgent ) ? "skip" : "test" ]
 );
 
 testIframe(
@@ -2931,11 +2892,8 @@ testIframe(
 		} );
 	},
 
-	// Support: Edge 18+, iOS 7-9 only, Android 4.0-4.4 only
+	// Support: Edge <=18+
 	// Edge doesn't support nonce in non-inline scripts.
 	// See https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/13246371/
-	// Old iOS & Android Browser versions support script-src but not nonce, making this test
-	// impossible to run. Browsers not supporting CSP at all are not a problem as they'll skip
-	// script-src restrictions completely.
-	QUnit[ /\bedge\/|iphone os [789]|android 4\./i.test( navigator.userAgent ) ? "skip" : "test" ]
+	QUnit[ /\bedge\//i.test( navigator.userAgent ) ? "skip" : "test" ]
 );
diff --git a/test/unit/offset.js b/test/unit/offset.js
index 2b63ccbd9..d18e6032f 100644
--- a/test/unit/offset.js
+++ b/test/unit/offset.js
@@ -4,26 +4,20 @@ if ( !jQuery.fn.offset ) {
 	return;
 }
 
-var supportsFixedPosition, supportsScroll, alwaysScrollable,
+var supportsScroll, alwaysScrollable,
 	forceScroll = supportjQuery( "<div/>" ).css( { width: 2000, height: 2000 } ),
 	checkSupport = function( assert ) {
 
 		// Only run once
 		checkSupport = false;
 
-		var checkFixed = supportjQuery( "<div/>" )
-			.css( { position: "fixed", top: "20px" } )
-			.appendTo( "#qunit-fixture" );
-		supportsFixedPosition = checkFixed[ 0 ].offsetTop === 20;
-		checkFixed.remove();
-
 		// Append forceScroll to the body instead of #qunit-fixture because the latter is hidden
 		forceScroll.appendTo( "body" );
 		window.scrollTo( 200, 200 );
 		supportsScroll = document.documentElement.scrollTop || document.body.scrollTop;
 		forceScroll.detach();
 
-		// Support: iOS <=7
+		// Support: iOS <=7 - 12+
 		// Hijack the iframe test infrastructure to detect viewport scrollability
 		// for pages with position:fixed document element
 		var done = assert.async();
@@ -400,22 +394,13 @@ testIframe( "fixed", "offset/fixed.html", function( assert, $, window ) {
 			assert.ok( true, "Browser doesn't support scroll position." );
 			assert.ok( true, "Browser doesn't support scroll position." );
 
-		} else if ( window.supportsFixedPosition ) {
+		} else {
 			assert.equal( jQuery.isPlainObject( $( this.id ).offset() ), true, "jQuery('" + this.id + "').offset() is plain object" );
 			assert.equal( jQuery.isPlainObject( $( this.id ).position() ), true, "jQuery('" + this.id + "').position() is plain object" );
 			assert.equal( $( this.id ).offset().top,  this.offsetTop,  "jQuery('" + this.id + "').offset().top" );
 			assert.equal( $( this.id ).position().top,  this.positionTop,  "jQuery('" + this.id + "').position().top" );
 			assert.equal( $( this.id ).offset().left, this.offsetLeft, "jQuery('" + this.id + "').offset().left" );
 			assert.equal( $( this.id ).position().left,  this.positionLeft,  "jQuery('" + this.id + "').position().left" );
-		} else {
-
-			// need to have same number of assertions
-			assert.ok( true, "Fixed position is not supported" );
-			assert.ok( true, "Fixed position is not supported" );
-			assert.ok( true, "Fixed position is not supported" );
-			assert.ok( true, "Fixed position is not supported" );
-			assert.ok( true, "Fixed position is not supported" );
-			assert.ok( true, "Fixed position is not supported" );
 		}
 	} );
 
@@ -429,40 +414,25 @@ testIframe( "fixed", "offset/fixed.html", function( assert, $, window ) {
 	];
 
 	jQuery.each( tests, function() {
-		if ( window.supportsFixedPosition ) {
-			$( this.id ).offset( { "top": this.top, "left": this.left } );
-			assert.equal( $( this.id ).offset().top,  this.top,  "jQuery('" + this.id + "').offset({ top: "  + this.top  + " })" );
-			assert.equal( $( this.id ).offset().left, this.left, "jQuery('" + this.id + "').offset({ left: " + this.left + " })" );
-
-			$( this.id ).offset( { "top": this.top, "left": this.left, "using": function( props ) {
-				$( this ).css( {
-					"top":  props.top  + 1,
-					"left": props.left + 1
-				} );
-			} } );
-			assert.equal( $( this.id ).offset().top,  this.top  + 1, "jQuery('" + this.id + "').offset({ top: "  + ( this.top  + 1 ) + ", using: fn })" );
-			assert.equal( $( this.id ).offset().left, this.left + 1, "jQuery('" + this.id + "').offset({ left: " + ( this.left + 1 ) + ", using: fn })" );
-		} else {
+		$( this.id ).offset( { "top": this.top, "left": this.left } );
+		assert.equal( $( this.id ).offset().top,  this.top,  "jQuery('" + this.id + "').offset({ top: "  + this.top  + " })" );
+		assert.equal( $( this.id ).offset().left, this.left, "jQuery('" + this.id + "').offset({ left: " + this.left + " })" );
 
-			// need to have same number of assertions
-			assert.ok( true, "Fixed position is not supported" );
-			assert.ok( true, "Fixed position is not supported" );
-			assert.ok( true, "Fixed position is not supported" );
-			assert.ok( true, "Fixed position is not supported" );
-		}
+		$( this.id ).offset( { "top": this.top, "left": this.left, "using": function( props ) {
+			$( this ).css( {
+				"top":  props.top  + 1,
+				"left": props.left + 1
+			} );
+		} } );
+		assert.equal( $( this.id ).offset().top,  this.top  + 1, "jQuery('" + this.id + "').offset({ top: "  + ( this.top  + 1 ) + ", using: fn })" );
+		assert.equal( $( this.id ).offset().left, this.left + 1, "jQuery('" + this.id + "').offset({ left: " + ( this.left + 1 ) + ", using: fn })" );
 	} );
 
 	// Bug 8316
 	$noTopLeft = $( "#fixed-no-top-left" );
-	if ( window.supportsFixedPosition ) {
-		assert.equal( $noTopLeft.offset().top,  1007,  "Check offset top for fixed element with no top set" );
-		assert.equal( $noTopLeft.offset().left, 1007, "Check offset left for fixed element with no left set" );
-	} else {
 
-		// need to have same number of assertions
-		assert.ok( true, "Fixed position is not supported" );
-		assert.ok( true, "Fixed position is not supported" );
-	}
+	assert.equal( $noTopLeft.offset().top, 1007, "Check offset top for fixed element with no top set" );
+	assert.equal( $noTopLeft.offset().left, 1007, "Check offset left for fixed element with no left set" );
 } );
 
 testIframe( "table", "offset/table.html", function( assert, $ ) {
@@ -660,25 +630,6 @@ QUnit.test( "chaining", function( assert ) {
 			}
 		} );
 
-		// Support: IE<=10 only
-		// Fudge the tests to work around <html>.gBCR() erroneously including margins
-		if ( /MSIE (?:9|10)\./.test( navigator.userAgent ) ) {
-			expectations.documentElement.pos.top -= expectations.documentElement.marginTop -
-				scrollTop;
-			expectations.documentElement.offset.top -= expectations.documentElement.marginTop -
-				scrollTop;
-			expectations.documentElement.pos.left -= expectations.documentElement.marginLeft -
-				scrollLeft;
-			expectations.documentElement.offset.left -= expectations.documentElement.marginLeft -
-				scrollLeft;
-			if ( htmlPos !== "static" ) {
-				delete expectations.documentElement;
-				delete expectations.body;
-				delete expectations.relative;
-				delete expectations.absolute;
-			}
-		}
-
 		return expectations;
 	}
 
@@ -803,10 +754,10 @@ QUnit.test( "fractions (see #7730 and #7885)", function( assert ) {
 
 	result = div.offset();
 
-	// Support: Chrome <=45 - 46
+	// Support: Chrome <=45 - 73+
 	// In recent Chrome these values differ a little.
 	assert.ok( Math.abs( result.top - expected.top ) < 0.25, "Check top within 0.25 of expected" );
-	assert.equal( result.left, expected.left, "Check left" );
+	assert.ok( Math.abs( result.left - expected.left ) < 0.25, "Check left within 0.25 of expected" );
 
 	div.remove();
 } );
@@ -816,13 +767,10 @@ QUnit.test( "iframe scrollTop/Left (see gh-1945)", function( assert ) {
 
 	var ifDoc = jQuery( "#iframe" )[ 0 ].contentDocument;
 
-	// Mobile Safari resize the iframe by its content meaning it's not possible to scroll
+	// Support: iOS <=8 - 12+
+	// Mobile Safari resizes the iframe by its content meaning it's not possible to scroll
 	// the iframe but only its parent element.
-	// It seems (not confirmed) in android 4.0 it's not possible to scroll iframes from the code.
-	if (
-		/iphone os|ipad/i.test( navigator.userAgent ) ||
-		/android 4\.0/i.test( navigator.userAgent )
-	) {
+	if ( /iphone os|ipad/i.test( navigator.userAgent ) ) {
 		assert.equal( true, true, "Can't scroll iframes in this environment" );
 		assert.equal( true, true, "Can't scroll iframes in this environment" );
 
diff --git a/test/unit/support.js b/test/unit/support.js
index b0309ffe7..e81e60c5d 100644
--- a/test/unit/support.js
+++ b/test/unit/support.js
@@ -36,7 +36,7 @@ if ( jQuery.css ) {
 }
 
 // This test checks CSP only for browsers with "Content-Security-Policy" header support
-// i.e. no old WebKit or old Firefox
+// i.e. no IE
 testIframe(
 	"Check CSP (https://developer.mozilla.org/en-US/docs/Security/CSP) restrictions",
 	"mock.php?action=cspFrame",
@@ -59,244 +59,63 @@ testIframe(
 		userAgent = window.navigator.userAgent,
 		expectedMap = {
 			edge: {
-				"ajax": true,
-				"boxSizingReliable": true,
-				"checkClone": true,
-				"checkOn": true,
-				"clearCloneStyle": true,
-				"cors": true,
-				"createHTMLDocument": true,
-				"noCloneChecked": true,
-				"optSelected": true,
-				"pixelBoxStyles": true,
-				"pixelPosition": true,
-				"radioValue": true,
-				"reliableMarginLeft": true,
-				"scrollboxSize": true
+				boxSizingReliable: true,
+				clearCloneStyle: true,
+				noCloneChecked: true,
+				optSelected: true,
+				radioValue: true
 			},
-			ie_10_11: {
-				"ajax": true,
-				"boxSizingReliable": false,
-				"checkClone": true,
-				"checkOn": true,
-				"clearCloneStyle": false,
-				"cors": true,
-				"createHTMLDocument": true,
-				"noCloneChecked": false,
-				"optSelected": false,
-				"pixelBoxStyles": true,
-				"pixelPosition": true,
-				"radioValue": false,
-				"reliableMarginLeft": true,
-				"scrollboxSize": true
-			},
-			ie_9: {
-				"ajax": true,
-				"boxSizingReliable": false,
-				"checkClone": true,
-				"checkOn": true,
-				"clearCloneStyle": false,
-				"cors": false,
-				"createHTMLDocument": true,
-				"noCloneChecked": false,
-				"optSelected": false,
-				"pixelBoxStyles": true,
-				"pixelPosition": true,
-				"radioValue": false,
-				"reliableMarginLeft": true,
-				"scrollboxSize": false
+			ie_11: {
+				boxSizingReliable: false,
+				clearCloneStyle: false,
+				noCloneChecked: false,
+				optSelected: false,
+				radioValue: false
 			},
 			chrome: {
-				"ajax": true,
-				"boxSizingReliable": true,
-				"checkClone": true,
-				"checkOn": true,
-				"clearCloneStyle": true,
-				"cors": true,
-				"createHTMLDocument": true,
-				"noCloneChecked": true,
-				"optSelected": true,
-				"pixelBoxStyles": true,
-				"pixelPosition": true,
-				"radioValue": true,
-				"reliableMarginLeft": true,
-				"scrollboxSize": true
+				boxSizingReliable: true,
+				clearCloneStyle: true,
+				noCloneChecked: true,
+				optSelected: true,
+				radioValue: true
 			},
 			safari: {
-				"ajax": true,
-				"boxSizingReliable": true,
-				"checkClone": true,
-				"checkOn": true,
-				"clearCloneStyle": true,
-				"cors": true,
-				"createHTMLDocument": true,
-				"noCloneChecked": true,
-				"optSelected": true,
-				"pixelBoxStyles": true,
-				"pixelPosition": true,
-				"radioValue": true,
-				"reliableMarginLeft": true,
-				"scrollboxSize": true
-			},
-			safari_9_10: {
-				"ajax": true,
-				"boxSizingReliable": true,
-				"checkClone": true,
-				"checkOn": true,
-				"clearCloneStyle": true,
-				"cors": true,
-				"createHTMLDocument": true,
-				"noCloneChecked": true,
-				"optSelected": true,
-				"pixelBoxStyles": false,
-				"pixelPosition": false,
-				"radioValue": true,
-				"reliableMarginLeft": true,
-				"scrollboxSize": true
+				boxSizingReliable: true,
+				clearCloneStyle: true,
+				noCloneChecked: true,
+				optSelected: true,
+				radioValue: true
 			},
 			firefox: {
-				"ajax": true,
-				"boxSizingReliable": true,
-				"checkClone": true,
-				"checkOn": true,
-				"clearCloneStyle": true,
-				"cors": true,
-				"createHTMLDocument": true,
-				"noCloneChecked": true,
-				"optSelected": true,
-				"pixelBoxStyles": true,
-				"pixelPosition": true,
-				"radioValue": true,
-				"reliableMarginLeft": true,
-				"scrollboxSize": true
-			},
-			firefox_60: {
-				"ajax": true,
-				"boxSizingReliable": true,
-				"checkClone": true,
-				"checkOn": true,
-				"clearCloneStyle": true,
-				"cors": true,
-				"createHTMLDocument": true,
-				"noCloneChecked": true,
-				"optSelected": true,
-				"pixelBoxStyles": true,
-				"pixelPosition": true,
-				"radioValue": true,
-				"reliableMarginLeft": false,
-				"scrollboxSize": true
+				boxSizingReliable: true,
+				clearCloneStyle: true,
+				noCloneChecked: true,
+				optSelected: true,
+				radioValue: true
 			},
 			ios: {
-				"ajax": true,
-				"boxSizingReliable": true,
-				"checkClone": true,
-				"checkOn": true,
-				"clearCloneStyle": true,
-				"cors": true,
-				"createHTMLDocument": true,
-				"noCloneChecked": true,
-				"optSelected": true,
-				"pixelBoxStyles": true,
-				"pixelPosition": true,
-				"radioValue": true,
-				"reliableMarginLeft": true,
-				"scrollboxSize": true
-			},
-			ios_9_10: {
-				"ajax": true,
-				"boxSizingReliable": true,
-				"checkClone": true,
-				"checkOn": true,
-				"clearCloneStyle": true,
-				"cors": true,
-				"createHTMLDocument": true,
-				"noCloneChecked": true,
-				"optSelected": true,
-				"pixelBoxStyles": false,
-				"pixelPosition": false,
-				"radioValue": true,
-				"reliableMarginLeft": true,
-				"scrollboxSize": true
-			},
-			ios_8: {
-				"ajax": true,
-				"boxSizingReliable": true,
-				"checkClone": true,
-				"checkOn": true,
-				"clearCloneStyle": true,
-				"cors": true,
-				"createHTMLDocument": false,
-				"noCloneChecked": true,
-				"optSelected": true,
-				"pixelBoxStyles": false,
-				"pixelPosition": false,
-				"radioValue": true,
-				"reliableMarginLeft": true,
-				"scrollboxSize": true
-			},
-			ios_7: {
-				"ajax": true,
-				"boxSizingReliable": true,
-				"checkClone": true,
-				"checkOn": true,
-				"clearCloneStyle": true,
-				"cors": true,
-				"createHTMLDocument": true,
-				"noCloneChecked": true,
-				"optSelected": true,
-				"pixelBoxStyles": false,
-				"pixelPosition": false,
-				"radioValue": true,
-				"reliableMarginLeft": true,
-				"scrollboxSize": true
-			},
-			android: {
-				"ajax": true,
-				"boxSizingReliable": true,
-				"checkClone": false,
-				"checkOn": false,
-				"clearCloneStyle": true,
-				"cors": true,
-				"createHTMLDocument": true,
-				"noCloneChecked": true,
-				"optSelected": true,
-				"pixelBoxStyles": false,
-				"pixelPosition": false,
-				"radioValue": true,
-				"reliableMarginLeft": false,
-				"scrollboxSize": true
+				boxSizingReliable: true,
+				clearCloneStyle: true,
+				noCloneChecked: true,
+				optSelected: true,
+				radioValue: true
 			}
 		};
 
 	if ( /edge\//i.test( userAgent ) ) {
 		expected = expectedMap.edge;
-	} else if ( /(msie 10\.0|trident\/7\.0)/i.test( userAgent ) ) {
-		expected = expectedMap.ie_10_11;
-	} else if ( /msie 9\.0/i.test( userAgent ) ) {
-		expected = expectedMap.ie_9;
+	} else if ( document.documentMode ) {
+		expected = expectedMap.ie_11;
 	} else if ( /chrome/i.test( userAgent ) ) {
 
-		// Catches Chrome on Android as well (i.e. the default
-		// Android browser on Android >= 4.4).
+		// Catches Chrome on Android & Opera as well.
 		expected = expectedMap.chrome;
-	} else if ( /\b(?:11|12)\.\d(\.\d+)* safari/i.test( userAgent ) ) {
+	} else if ( /\b\d+(\.\d+)+ safari/i.test( userAgent ) ) {
 		expected = expectedMap.safari;
-	} else if ( /\b(?:9|10)\.\d(\.\d+)* safari/i.test( userAgent ) ) {
-		expected = expectedMap.safari_9_10;
-	} else if ( /firefox\/(?:52|60)/i.test( userAgent ) ) {
-		expected = expectedMap.firefox_60;
 	} else if ( /firefox/i.test( userAgent ) ) {
 		expected = expectedMap.firefox;
-	} else if ( /(?:iphone|ipad);.*(?:iphone)? os (?:11|12)_/i.test( userAgent ) ) {
+	} else if ( /(?:iphone|ipad);.*(?:iphone)? os \d+_/i.test( userAgent ) ) {
 		expected = expectedMap.ios;
-	} else if ( /iphone os (?:9|10)_/i.test( userAgent ) ) {
-		expected = expectedMap.ios_9_10;
-	} else if ( /iphone os 8_/i.test( userAgent ) ) {
-		expected = expectedMap.ios_8;
-	} else if ( /iphone os 7_/i.test( userAgent ) ) {
-		expected = expectedMap.ios_7;
-	} else if ( /android 4\.[0-3]/i.test( userAgent ) ) {
-		expected = expectedMap.android;
 	}
 
 	QUnit.test( "Verify that support tests resolve as expected per browser", function( assert ) {
@@ -315,13 +134,9 @@ testIframe(
 		assert.expect( j );
 
 		for ( i in expected ) {
-			if ( jQuery.ajax || i !== "ajax" && i !== "cors" ) {
-				assert.equal( computedSupport[ i ], expected[ i ],
-					"jQuery.support['" + i + "']: " + computedSupport[ i ] +
-						", expected['" + i + "']: " + expected[ i ] );
-			} else {
-				assert.ok( true, "no ajax; skipping jQuery.support['" + i + "']" );
-			}
+			assert.equal( computedSupport[ i ], expected[ i ],
+				"jQuery.support['" + i + "']: " + computedSupport[ i ] +
+					", expected['" + i + "']: " + expected[ i ] );
 		}
 	} );
 
@@ -331,10 +146,7 @@ testIframe(
 		var prop, browserKey, supportTestName,
 			i = 0,
 			supportProps = {},
-			failingSupportProps = {},
-			whitelist = {
-				ajax: true
-			};
+			failingSupportProps = {};
 
 		for ( prop in computedSupport ) {
 			i++;
@@ -342,8 +154,8 @@ testIframe(
 
 		assert.expect( i );
 
-		// Record all support props and the failing ones and ensure everyone
-		// except a few on a whitelist are failing at least once.
+		// Record all support props and the failing ones and ensure every test
+		// is failing at least once.
 		for ( browserKey in expectedMap ) {
 			for ( supportTestName in expectedMap[ browserKey ] ) {
 				supportProps[ supportTestName ] = true;
@@ -354,8 +166,9 @@ testIframe(
 		}
 
 		for ( supportTestName in supportProps ) {
-			assert.ok( whitelist[ supportTestName ] || failingSupportProps[ supportTestName ],
-				"jQuery.support['" + supportTestName + "'] always succeeds; remove it?" );
+			assert.ok( failingSupportProps[ supportTestName ],
+				"jQuery.support['" + supportTestName +
+					"'] is expected to fail at least in one browser" );
 		}
 	} );