function addLoadEvent(func) {var oldonload = window.onload; //得到上一个onload函数if (typeof window.onload != "function") { //判断类型是否为functionwindow.onload = func;}else {window.onload = function () {oldonload(); //调用之前覆盖的Onloadfunc();//执行当前函数}}}
原文：http://www.cnblogs.com/TT-Cartier/p/4695015.html