javascript前端：封装array的foreach方法

if (!Array.prototype.forEach) {
 Array.prototype.forEach = function forEach(callback, thisArg) {
 var T, k;
 if (this == null) {
 throw new TypeError("this is null or not defined");
 }
 var O = Object(this);
 var len = O.length >>> 0;
 if (typeof callback !== "function") {
 throw new TypeError(callback + " is not a function");
 }
 if (arguments.length > 1) {
 T = thisArg;
 }
 k = 0;
 while (k < len) {
 var kValue;
 if (k in O) {
 kValue = O[k];
 callback.call(T, kValue, k, O);
 }
 k++;
 }
 };
}
这里用到了prototype原型链

<script>
var vModel=[1,2,3,4] ; 
vModel.forEach(function (item, index) {
 console.log("值:"+item+"---序号："+index)
 });
</script>