Revert 8d1c42296fefc4e79189b6c2d78a8a78fdd9576d

1 files changed, 3 insertions, 8 deletions

diff --git a/src/core.js b/src/core.js
index 39e68c4fc..cae3a90e3 100644
--- a/src/core.js
+++ b/src/core.js
@@ -422,11 +422,8 @@ jQuery.extend({
 	},
 
 	isPlainObject: function( obj ) {
-		var key;
 		// Not plain objects:
 		// - Any object or value whose internal [[Class]] property is not "[object Object]"
-		//   ...Unless it was a constructor, whose prototype property was paved over by
-		//   by a plain object at its declaration. #13571
 		// - DOM nodes
 		// - window
 		if ( jQuery.type( obj ) !== "object" || obj.nodeType || jQuery.isWindow( obj ) ) {
@@ -445,11 +442,9 @@ jQuery.extend({
 			return false;
 		}
 
-		// Own properties are enumerated firstly, so to speed up,
-		// if last one is own, then all properties are own.
-		for ( key in obj ) {}
-
-		return key === undefined || core_hasOwn.call( obj, key );
+		// If the function hasn't returned already, we're confident that
+		// |obj| is a plain object, created by {} or constructed with new Object
+		return true;
 	},
 
 	isEmptyObject: function( obj ) {