1 if (jQuery && !jQuery.fn.forEach) { 2     $(function () { 3         (function ($) { 4             $.fn.extend({ 5                 forEach: function (predicate) { 6  7                     if (this == null) { 8                         throw new TypeError(‘ this is null or not defined‘); 9                     }10 11                     // 1. Let O be the result of calling toObject() passing the12                     // |this| value as the argument.13                     var O = Object(this);14 15                     // 2. If isCallable(predicate) is false, throw a TypeError exception. 16                     if (typeof predicate !== "function") {17                         throw new TypeError(predicate + ‘ is not a function‘);18                     }19 20                     //3 call the jq  original API  for iteror21                     $.each(O, function (index, domEle) {22                         predicate($(domEle));23                     });24                 }25             })26         })(jQuery);27 28     });29 }