window.onload绑定多个函数

 1 function addLoadEvent(fun) {
 2     var oldonload = window.onload;
 3     if (typeof window.onload != 'funcation') {
 4         window.onload = fun;
 5     }
 6     else {
 7         window.onload = function () {
 8             oldonload();
 9             fun();
10         }
11     }
12 }