1 //判断函数行参长度来决定是否需要重写setTimeout，ie8以下为undefined 2 if(window.setTimeout.length == undefined){ 3     var __sto = window.setTimeout; 4     window.setTimeout = function(callback,timeout,param){ 5         var args = Array.prototype.slice.call(arguments,2); 6         __sto(function(){ 7             callback.apply(null,args); 8         },timeout); 9     };10 }