Index: test/unit/core.js
===================================================================
--- test/unit/core.js	(revision 6090)
+++ test/unit/core.js	(working copy)
@@ -1574,7 +1574,7 @@
 });
 
 test("toggleClass(String)", function() {
-	expect(6);
+	expect(16);
 	var e = jQuery("#firstp");
 	ok( !e.is(".test"), "Assert class not present" );
 	e.toggleClass("test");
@@ -1588,6 +1588,33 @@
 	ok( e.is(".test"), "Assert class present" );
 	e.toggleClass("test", false);
 	ok( !e.is(".test"), "Assert class not present" );
+	
+	e.addClass("testA testB");
+	ok( (e.is(".testA") && e.is(".testB")), "Assert 2 different classes present" );
+	e.toggleClass("testB testC");
+	ok( (e.is(".testA") && !e.is(".testB") && e.is(".testC")), "Assert 1 class added, 1 class removed and 1 class keeped" );
+	e.toggleClass("testA testC");
+	ok( (!e.is(".testA") && !e.is(".testB") && !e.is(".testC")), "Assert no class present" );
+	
+	// toggleClass storage
+	e.toggleClass(true);
+	ok( e.get(0).className === '', "Assert class is empty (data was empty)" );
+	e.addClass("testD");
+	ok( e.is(".testD"), "Assert class present" );
+	e.toggleClass();
+	ok( !e.is(".testD"), "Assert class not present" );
+	ok( e.data('originalClassName') == 'testD', "Assert data was stored" );
+	e.toggleClass();
+	ok( e.is(".testD"), "Assert class present (restored from data)" );
+	e.toggleClass(false);
+	ok( !e.is(".testD"), "Assert class not present" );
+	e.toggleClass(true);
+	ok( e.is(".testD"), "Assert class present (restored from data)" );
+	
+	// Cleanup
+	e.removeClass("testD");
+	e.removeData('originalClassName')
+	
 });
 
 test("removeAttr(String", function() {
Index: src/core.js
===================================================================
--- src/core.js	(revision 6090)
+++ src/core.js	(working copy)
@@ -1202,9 +1202,17 @@
 	},
 
 	toggleClass: function( classNames, state ) {
-		if( typeof state !== "boolean" )
-			state = !jQuery.className.has( this, classNames );
-		jQuery.className[ state ? "add" : "remove" ]( this, classNames );
+		if(!classNames || typeof classNames === "boolean") {
+			if( !(classNames = jQuery.data(this, 'originalClassName')) && !this.className ) return;
+			state = this.className ? !(jQuery.data(this, 'originalClassName', classNames = this.className)) : true;
+		}
+		var elem = this;
+		jQuery.each((classNames || "").split(/\s+/), function(i, className){
+			var force = ( typeof state !== "boolean" ) ?
+					!jQuery.className.has( elem, className ) :
+					state;
+			jQuery.className[ force ? "add" : "remove" ]( elem, className );
+		});
 	},
 
 	remove: function( selector ) {