Index: traversing.js
===================================================================
--- traversing.js	(revision 6308)
+++ traversing.js	(working copy)
@@ -34,13 +34,14 @@
 			}) ), "filter", selector );
 	},
 
-	closest: function( selector ) {
+	closest: function( selector, context ) {
 		var pos = jQuery.expr.match.POS.test( selector ) ? jQuery(selector) : null,
-			closer = 0;
+			closer = 0,
+			stopElement = ( context && context.parentNode ) ? context.parentNode : false;;
 
 		return this.map(function(){
 			var cur = this;
-			while ( cur && cur.ownerDocument ) {
+			while ( cur && cur.ownerDocument && stopElement !== cur) {
 				if ( pos ? pos.index(cur) > -1 : jQuery(cur).is(selector) ) {
 					jQuery.data(cur, "closest", closer);
 					return cur;