function GetQueryString(name){
var reg = new RegExp("(^|&)"+ name +"=([^&]*)(&|$)");
var r = window.location.search.substr(1).match(reg);
if(r!=null)
return unescape(r[2]); return null;
}
var webcast=GetQueryString("webcast");
原文：http://www.cnblogs.com/pangxiaorong/p/7808230.html