Fixes #13714. jQuery.globalEval gotcha w/ strings that contain valid, prologue position strict mode pragma

Signed-off-by: Rick Waldron <waldron.rick@gmail.com>

2 files changed, 27 insertions, 4 deletions

diff --git a/src/core.js b/src/core.js
index cae3a90e3..e37627459 100644
--- a/src/core.js
+++ b/src/core.js
@@ -515,10 +515,25 @@ jQuery.extend({
 	noop: function() {},
 
 	// Evaluates a script in a global context
-	globalEval: function( data ) {
-		var indirect = eval;
-		if ( jQuery.trim( data ) ) {
-			indirect( data + ";" );
+	globalEval: function( code ) {
+		var script,
+				indirect = eval;
+
+		code = jQuery.trim( code ) + ";";
+
+		if ( code ) {
+			// If the code includes a valid, prologue position
+			// strict mode pragma, execute code by injecting a
+			// script tag into the document.
+			if ( code.indexOf("use strict") === 1 ) {
+				script = document.createElement("script");
+				script.text = code;
+				document.head.appendChild( script ).parentNode.removeChild( script );
+			} else {
+			// Otherwise, avoid the DOM node creation, insertion
+			// and removal by using an indirect global eval
+				indirect( code );
+			}
 		}
 	},
 
diff --git a/test/unit/core.js b/test/unit/core.js
index 7c840993b..6cdd3b93d 100644
--- a/test/unit/core.js
+++ b/test/unit/core.js
@@ -215,6 +215,14 @@ test( "globalEval", function() {
 	equal( window.globalEvalTest, 3, "Test context (this) is the window object" );
 });
 
+test( "globalEval with 'use strict'", function() {
+	expect( 1 );
+	Globals.register("strictEvalTest");
+
+	jQuery.globalEval("'use strict'; var strictEvalTest = 1;");
+	equal( window.strictEvalTest, 1, "Test variable declarations are global (strict mode)" );
+});
+
 test("noConflict", function() {
 	expect(7);