ie8 不支持javascript map 方法

if (!Array.prototype.map) { Array.prototype.map = function(callback, thisArg) { var T, A, k; if (this == null) { throw new TypeError(" this is null or not defined"); } var O = Object(this); var len = O.length >>> 0; if (Object.prototype.toString.call(callback) != "[object Function]") { throw new TypeError(callback + " is not a function"); } if (thisArg) { T = thisArg; } A = new Array(len); k = 0; while(k