function get_cookie(cookie_name)
{
    if (document.cookie.length > 0) {              
    begin = document.cookie.indexOf(cookie_name+"=");       
    if (begin != -1) {           
      begin += cookie_name.length+1;       
      end = document.cookie.indexOf(";", begin);
      if (end == -1) end = document.cookie.length;
        return unescape(document.cookie.substring(begin, end));
    } 
  }
  return null;
}

function set_screen_res_cookie()
{
 cookie_resolution = get_cookie("users_resolution");
 if (cookie_resolution == null)
 {
   var today = new Date();
   var the_date = new Date("December 31, 2023");
   var the_cookie_date = the_date.toGMTString();
   var the_cookie = "users_resolution="+ screen.width +"x"+ screen.height;
   var the_cookie = the_cookie + ";expires=" + the_cookie_date;
   document.cookie=the_cookie
 }
}

set_screen_res_cookie();