text: let upgradeTime = 7200;
  let seconds = upgradeTime;
  function timer() {
    let days        = Math.floor(seconds/24/60/60);
    let hoursLeft   = Math.floor((seconds) - (days*86400));
    let hours       = Math.floor(hoursLeft/3600);
    let minutesLeft = Math.floor((hoursLeft) - (hours*3600));
    let minutes     = Math.floor(minutesLeft/60);
    let remainingSeconds = seconds % 60;
    function pad(n) {
      return (n < 10 ? "0" + n : n);
    }
    document.getElementById('countdown').innerHTML = pad(hours) + ":" + pad(minutes) + ":" + pad(remainingSeconds);
    if (seconds == 0) {
      clearInterval(countdownTimer);
      document.getElementById('countdown').innerHTML = "Completed";
    } else {
      seconds--;
    }
  }
  let countdownTimer = setInterval('timer()', 1000);