function getCookie(NameOfCookie) {
   //check if any cookies are on page
   if (document.cookie.length > 0) {

      //look for our cookie
      begin = document.cookie.indexOf(NameOfCookie+"=");
      if (begin != -1) {
         begin += NameOfCookie.length+1;
         end = document.cookie.indexOf(";", begin);
         if (end == -1) 
            end = document.cookie.length;
         return unescape(document.cookie.substring(begin, end)); 
      }
   }
   return null;
}

function setCookie(NameOfCookie, value, expiredays) {
   var ExpireDate = new Date ();
   ExpireDate.setTime(ExpireDate.getTime() + (expiredays * 24 * 3600 * 1000));

   document.cookie = NameOfCookie + "=" + escape(value) + ((expiredays == null) ? "" : "; expires=" + ExpireDate.toGMTString());
}

function delCookie (NameOfCookie) {
   if (getCookie(NameOfCookie)) {
      document.cookie = NameOfCookie + "=" + "; expires=Thu, 01-Jan-70 00:00:01 GMT";
   }
}