Let popup once for event dialog or something like that in Javascript

var expDays = 1; // number of days the cookie should last

var page = "only-popup-once.html";
var windowprops = "width=300,height=200,location=no,toolbar=no,menubar=no,scrollbars=no,resizable=yes";

function GetCookie (name) {
  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 null;
}

function SetCookie (name,value) {
  var argv = SetCookie.arguments;
  var argc = SetCookie.arguments.length;
  var expires = (argc > 2) ? argv[2] : null;
  var path = (argc > 3) ? argv[3] : null;
  var domain = (argc > 4) ? argv[4] : null;
  var secure = (argc > 5) ? argv[5] : false;
  document.cookie = name   "="   escape (value) 
    ((expires == null) ? "" : ("; expires="   expires.toGMTString())) 
    ((path == null) ? "" : ("; path="   path)) 
    ((domain == null) ? "" : ("; domain="   domain)) 
    ((secure == true) ? "; secure" : "");
}

function DeleteCookie (name) {
  var exp = new Date();
  exp.setTime (exp.getTime() - 1);
  var cval = GetCookie (name);
  document.cookie = name   "="   cval   "; expires="   exp.toGMTString();
}

var exp = new Date();
exp.setTime(exp.getTime()   (expDays*24*60*60*1000));

function amt(){
  var count = GetCookie('count')
  if(count == null) {
    SetCookie('count','1')
    return 1
  } else {
    var newcount = parseInt(count)   1;
    DeleteCookie('count')
    SetCookie('count',newcount,exp)
    return count
  }
}

function getCookieVal(offset) {
  var endstr = document.cookie.indexOf (";",offset);
  if (endstr == -1)
  endstr = document.cookie.length;
  return unescape(document.cookie.substring(offset,endstr));
}

function checkCount() {
  var count = GetCookie('count');
  if (count == null) {
    count=1;
    SetCookie('count',count,exp);
    window.open(page,"",windowprops);
  } else {
    count  ;
    SetCookie('count',count,exp);
  }
}

window.onload=checkCount;

<html>
<head>
  <title>KURAPA.COM Event</title>
  <script type="text/javascript" src="onlyPopupOnce.js"></script>
</head>
<body>
.
.
.
</body>
</html>