function getCookie(NameOfCookie) {
      if (document.cookie.length > 0) {
        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 " ";
    }

    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";
      }
    }