Jquery 对象集合的迭代扩展forEach

 if (jQuery && !jQuery.fn.forEach) {
     $(function () {
         (function ($) {
             $.fn.extend({
                 forEach: function (predicate) {

                     if (this == null) {
                         throw new TypeError(' this is null or not defined');
                     }

                     // 1. Let O be the result of calling toObject() passing the
                     // |this| value as the argument.
                     var O = Object(this);

                     // 2. If isCallable(predicate) is false, throw a TypeError exception.
                     if (typeof predicate !== "function") {
                         throw new TypeError(predicate + ' is not a function');
                     }

                     //3 call the jq  original API  for iteror
                     $.each(O, function (index, domEle) {
                         predicate($(domEle));
                     });
                 }
             })
         })(jQuery);

     });
 }