Countdown timer

by Vladimir Zharinov

HTML

<div id="countdown"></div>
<div id="countdown2"></div>

CSS

div {
  color: #1B232F;
  font-family: Verdana, Arial, sans-serif;
  font-size: 18px;
  font-weight: bold;
  text-decoration: none;
}

JavaScript

function countdown(elementName, minutes, seconds) {
  var element, endTime, hours, mins, msLeft, time;

  function twoDigits(n) {
    return (n <= 9 ? "0" + n : n);
  }

  function updateTimer() {
    msLeft = endTime - (+new Date);
    if (msLeft < 1000) {
      element.innerHTML = "Таймер истек!";
    } else {
      time = new Date(msLeft);
      hours = time.getUTCHours();
      mins = time.getUTCMinutes();
      element.innerHTML = (hours ? hours + ':' + twoDigits(mins) : mins) + ':' + twoDigits(time.getUTCSeconds());
      setTimeout(updateTimer, time.getUTCMilliseconds() + 500);
    }
  }

  element = document.getElementById(elementName);
  endTime = (+new Date) + 1000 * (60 * minutes + seconds) + 500;
  updateTimer();
}

countdown("countdown", 0, 5);
countdown("countdown2", 100, 0);