Javascript做出刷新本页时同时打开另一页,如何让它只打开一次?

<script language="javascript">
function setCookie(name,value)
{
var Days = 30;
var exp = new Date();
exp.setTime(exp.getTime() + Days*24*60*60*1000);
document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString();
}
function getCookie(name)
{
var arr,reg=new RegExp("(^| )"+name+"=([^;]*)(;|$)");
if(arr=document.cookie.match(reg)) return unescape(arr[2]);
else return null;
}

if(getCookie('a')=="")
{
window.open('aaa.asp','_blank','');
setCookie('a','a');
}
</script>

定义一个全局变量，标记一下

直接用ASP简单处理即可:
<%
if session("k")="" then
response.write("<script language=javascript>window.open('AAA.asp?")</script> ")
else
session("k")="4"
end if