var up, down;
  var min1, sec1;
  var cmin1, csec1, cmin2, csec2;

   
   function popup(url, width, height)
  {
      day = new Date();
      id = day.getTime();
      eval("page" + id + " = window.open(url, '" + id + "', 'toolbar = 0, scrollbars = 0, location = 0, statusbar = 0, menubar = 0, resizable = 1, width = " + width + ", height = " + height + "');");
  }

  function goto_url(object)
  {
      window.location.href = object.options[object.selectedIndex].value;
  }

  function minutes(data)
  {
      for (var i = 0; i <data.length; i++) if (data.substring(i, i + 1) == ":") break;
      return (data.substring(0, i));
  }

  function seconds(data)
  {
      for (var i = 0; i <data.length; i++) if(data.substring(i, i + 1) == ":") break;
      return (data.substring(i + 1, data.length));
  }

  function Display(min, sec)
  {
      var disp;
      if (min <= 9) disp = "0";
      else disp = " ";
      disp += min + ":";
      if (sec <= 9) disp += "0" + sec;
      else disp += sec;
      return (disp);
  }

  function Down()
  {
      cmin2 = 1 * minutes(document.countdown.start_time.value);
      csec2 = 0 + seconds(document.countdown.start_time.value);
      DownRepeat();
  }

  function DownRepeat()
  {
      if (--csec2 == -1) {
          csec2 = 59;
          cmin2--;
      }

      document.countdown.time.value = Display(cmin2, csec2);
      if ((cmin2 == 0) && (csec2 == 0)) alert("Waktu ujian sudah habis!");
      else down = setTimeout("DownRepeat()", 1000);
  }