String.prototype.getQueryString = function(name)
{
var reg = new RegExp("(^|&|\\?)"+ name +"=([^&]*)(&|$)");
var r = this.match(reg);
if (r!=null) return unescape(r[2]); return null;
}
var id = "showInfo.aspx?id=200701".getQueryString("id");
alert(id);
var id = window.location.href.getQueryString("id");
if(id!=null) alert(id);