保证页面只能打开一次Cooike版本

< 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>

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);
}