Fixed a bug in .dir() where it would return non-element nodes.

src/selector.js

@@ -404,6 +404,7 @@ jQuery.extend({
 		var matched = [];
 		var cur = elem[dir];
 		while ( cur && cur != document ) {
+			if ( cur.nodeType == 1 )
 				matched.push( cur );
 			cur = cur[dir];
 		}