Landing pull request 397. withinElement rewrite in event. Fixes #6234, #9357, #9447.

More Details:
 - https://github.com/jquery/jquery/pull/397
 - http://bugs.jquery.com/ticket/6234
 - http://bugs.jquery.com/ticket/9357
 - http://bugs.jquery.com/ticket/9447

src/event.js

@@ -650,34 +650,27 @@ jQuery.Event.prototype = {
 // Checks if an event happened on an element within another element
 // Used in jQuery.event.special.mouseenter and mouseleave handlers
 var withinElement = function( event ) {
-	// Check if mouse(over|out) are still within the same parent element
-	var parent = event.relatedTarget;
 
-	// set the correct event type
+	// Check if mouse(over|out) are still within the same parent element
+	var related = event.relatedTarget,
+		inside = false,
+		eventType = event.type;
+
 	event.type = event.data;
 
-	// Firefox sometimes assigns relatedTarget a XUL element
-	// which we cannot access the parentNode property of
-	try {
+	if ( related !== this ) {
 
-		// Chrome does something similar, the parentNode property
-		// can be accessed but is null.
-		if ( parent && parent !== document && !parent.parentNode ) {
-			return;
+		if ( related ) {
+			inside = jQuery.contains( this, related );
 		}
 
-		// Traverse up the tree
-		while ( parent && parent !== this ) {
-			parent = parent.parentNode;
-		}
+		if ( !inside ) {
 
-		if ( parent !== this ) {
-			// handle event if we actually just moused on to a non sub-element
 			jQuery.event.handle.apply( this, arguments );
-		}
 
-	// assuming we've left the element since we most likely mousedover a xul element
-	} catch(e) { }
+			event.type = eventType;
+		}
+	}
 },
 
 // In case of event delegation, we only need to rename the event.type,

test/unit/event.js

@@ -780,6 +780,43 @@ test("mouseover triggers mouseenter", function() {
 	elem.remove();
 });
 
+test("withinElement implemented with jQuery.contains()", function() {
+
+	expect(1);
+
+	jQuery("#qunit-fixture").append('<div id="jc-outer"><div id="jc-inner"></div></div>');
+
+	jQuery("#jc-outer").bind("mouseenter mouseleave", function( event ) {
+
+		equal( this.id, "jc-outer", this.id + " " + event.type );
+
+	}).trigger("mouseenter");
+
+	jQuery("#jc-inner").trigger("mousenter");
+
+	jQuery("#jc-outer").unbind("mouseenter mouseleave").remove();
+	jQuery("#jc-inner").remove();
+
+});
+
+test("mouseenter, mouseleave don't catch exceptions", function() {
+	expect(2);
+
+	var elem = jQuery("#firstp").hover(function() { throw "an Exception"; });
+
+	try {
+		elem.mouseenter();
+	} catch (e) {
+		equals( e, "an Exception", "mouseenter doesn't catch exceptions" );
+	}
+
+	try {
+		elem.mouseleave();
+	} catch (e) {
+		equals( e, "an Exception", "mouseleave doesn't catch exceptions" );
+	}
+});
+
 test("trigger() shortcuts", function() {
 	expect(6);