利用JS获取这个A，(strid就是A)
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default2.aspx.cs" Inherits="Default2" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<script type="text/JavaScript">
function Getid() {
var url = location.search;
var strid;
if (url.indexOf("?") != -1) {
strid = url.substr(url.indexOf("?") + 4, url.indexOf("&") - url.indexOf("?") - 4);
}
window.location.href = "Default.aspx?id=" + strid;
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<a href="javascript:Getid();">打开新页面，传递ID为A的</a>
</div>
</form>
</body>
</html>
