页面只能打开一次Cooike如何实现

最近在做webIM,嵌入到OA系统,由于WEBIM处在独立页面,所以如果多次点击就会出现多个页面,这样在IE6下,服务器推送会认不到页面.所以有了下面的代码:

<script language="javascript" type="text/javascript"> 
window.onload = function () { 
if (GetCookie("IsOpen") == "") { 
SetCookie("IsOpen", "1"); 
StartService(); 
} else { 
window.onunload = null; 
window.opener = null; 
window.open("", "_self"); 
window.close(); 
} 
} window.onunload = function () { 
if (GetCookie("IsOpen") != "") 
DeleteCookie("IsOpen"); 
} 
function GetCookieVal(offset) { 
/// <summary> 
/// //取得项名称为offset的cookie值 
/// </summary> 
/// <param name="name">Cookie名称</param> 
var endstr = document.cookie.indexOf(";", offset); 
if (endstr == -1) 
endstr = document.cookie.length; 
return unescape(document.cookie.substring(offset, endstr)); 
} 
function GetCookie(name) { 
/// <summary> 
/// 根据名称获得Cookie值 
/// </summary> 
/// <param name="name">Cookie名称</param> 
var arg = name + "="; 
var alen = arg.length; 
var clen = document.cookie.length; 
var i = 0; 
while (i < clen) { 
var j = i + alen; 
if (document.cookie.substring(i, j) == arg) 
return GetCookieVal(j); 
i = document.cookie.indexOf(" ", i) + 1; 
if (i == 0) break; 
} 
return ""; 
} 
function SetCookie(name, value) { 
/// <summary> 
/// 设置Cookie 
/// </summary> 
/// <param name="name">Cookie名称</param> 
/// <param name="value">Cookie值</param> 
var argc = SetCookie.arguments.length; 
var argv = SetCookie.arguments; 
var path = (argc > 3) ? argv[3] : null; 
var domain = (argc > 4) ? argv[4] : null; 
var secure = (argc > 5) ? argv[5] : false; 
document.cookie = name + "=" + value + 
((path == null) ? "" : ("; path=" + path)) + 
((domain == null) ? "" : ("; domain=" + domain)) + 
((secure == true) ? "; secure" : ""); 
} 
function DeleteCookie(name) { 
/// <summary> 
/// 删除Cookie 
/// </summary> 
/// <param name="name">Cookie名称</param> 
var exp = new Date(); 
exp.setTime(exp.getTime() - 1); 
var cval = GetCookie(name); 
document.cookie = name + "=" + cval + "; expires=" + exp.toGMTString(); 
} 
</script>

把上面的代码,放到head下面就可以了.呵呵够简单了吧?当然上面的代码主要解决的是用超链接打开的页面,如果是window.open打开的页面呢,那就更简单了,代码如下:

var win = null;//定义一个变量去判断就可以了 
if (win == null) 
{ 
win=window.open("Main.aspx", '', strfeatures); 
}