保证页面只能打开一次Cooike版本

   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);
    }