JS弹窗代码，只弹一次

function setCookie(name, value, expire) { 
window.document.cookie = name + "=" + escape(value) + ((expire == null) ? "" : ("; expires=" + expire.toGMTString()));
}
function getCookie(Name) { 
var search = Name + "=";
if (window.document.cookie.length > 0) { // if there are any cookies
offset = window.document.cookie.indexOf(search);
if (offset != -1) { // if cookie exists
offset += search.length; // set index of beginning of value
end = window.document.cookie.indexOf(";", offset) // set index of end of cookie value
if (end == -1)
end = window.document.cookie.length;
return unescape(window.document.cookie.substring(offset, end));
}
}
return null;
}
function register(name) {
var today = new Date();
var expires = new Date();
expires.setTime(today.getTime() + 1000*60*60*24);
setCookie("gu90com", name, expires);
}
var exitURL="https://www.gu90.com";
function openWin() {
var c = getCookie("gu90com");
if (c != null) {
return;
}
register("gu90com");
var featureStr="''";
featureStr="'top=0,left=0,width=800,height=600,toolbar=yes, menubar=no, scrollbars=no, resizable=no, location=no, status=no,center:no'";
self.focus();
var ExitWindow = window.open(exitURL); 
ExitWindow.focus();
}
openWin();
window.focus();