Ticket #3134: toString.diff

src/core.js

@@ -615 +615 @@
         // See test/unit/core.js for details concerning this function.
         isFunction: function( fn ) {
                 return !!fn && typeof fn != "string" && !fn.nodeName &&
-                        fn.constructor != Array && /^[\s[]?function/.test( fn + "" );
+                        fn.constructor != Array && /^[\s[]?function/.test( Object.toString.call(fn) );
         },
 
         // check if an element is in a (or is an) XML document