ie8下array的map()方法不支持

/*ie 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(typeof callback!=="function"){throw new TypeError(callback+" is not a function");}if(thisArg){T=thisArg}A=new Array(len);k=0;while(k<len){var kValue,mappedValue;if(k in O){kValue=O[k];mappedValue=callback.call(T,kValue,k,O);A[k]=mappedValue}k++}return A}}