<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); }