Fix regression in add and append in IE after revision 3463

src/core.js

@@ -331,7 +331,12 @@ jQuery.fn = jQuery.prototype = {
 	},
 
 	add: function( selector ) {
-		return this.pushStack( jQuery.merge( this.get(), jQuery( selector ) ) );
+		return this.pushStack( jQuery.merge( 
+			this.get(),
+			selector.constructor == String ? 
+				jQuery( selector ).get() :
+				selector.length != undefined && (!selector.nodeName || jQuery.nodeName(selector, "form")) ?
+					selector : [selector] ) );
 	},
 
 	is: function( selector ) {
@@ -948,7 +953,7 @@ jQuery.extend({
 						div.firstChild && div.firstChild.childNodes :
 						
 						// String was a bare <thead> or <tfoot>
-						wrap[1] == "<table>" && s.indexOf("<tbody") < 0 ?
+						wrap[1] == "<table>" && tags.indexOf("<tbody") < 0 ?
 							div.childNodes :
 							[];