Javascript - countdown timer

Question

I have this JS code for countdown function. Currently it is counting 1min = 60sec. All I need is after counting 60sec to show on page "COUNTING FINISHED!". Here is my code:

<h1>Countdown Clock</h1>
<div id="clockdiv">
  <div>
    <span class="days"></span>
    <div class="smalltext">Days</div>
  </div>
  <div>
    <span class="hours"></span>
    <div class="smalltext">Hours</div>
  </div>
  <div>
    <span class="minutes"></span>
    <div class="smalltext">Minutes</div>
  </div>
  <div>
    <span class="seconds"></span>
    <div class="smalltext">Seconds</div>
  </div>
</div>

and script:

function getTimeRemaining(endtime) {
  var t = Date.parse(endtime) - Date.parse(new Date());
  var seconds = Math.floor((t / 1000) % 60);
  var minutes = Math.floor((t / 1000 / 60) % 60);
  var hours = Math.floor((t / (1000 * 60 * 60)) % 24);
  var days = Math.floor(t / (1000 * 60 * 60 * 24));
  return {
    'total': t,
    'days': days,
    'hours': hours,
    'minutes': minutes,
    'seconds': seconds
  };
}

function initializeClock(id, endtime) {
  var clock = document.getElementById(id);
  var daysSpan = clock.querySelector('.days');
  var hoursSpan = clock.querySelector('.hours');
  var minutesSpan = clock.querySelector('.minutes');
  var secondsSpan = clock.querySelector('.seconds');

  function updateClock() {
    var t = getTimeRemaining(endtime);

    daysSpan.innerHTML = t.days;
    hoursSpan.innerHTML = ('0' + t.hours).slice(-2);
    minutesSpan.innerHTML = ('0' + t.minutes).slice(-2);
    secondsSpan.innerHTML = ('0' + t.seconds).slice(-2);

    if (t.total <= 0) {
      clearInterval(timeinterval);
    }
  }

  updateClock();
  var timeinterval = setInterval(updateClock, 1000);
}

var deadline = new Date(Date.parse(new Date()) + 60 * 1000);
initializeClock('clockdiv', deadline);

After the last </div> I need to put text "COUNTING FINISHED!" after counting expires. Is any way to do it with if statement? Please help!

Answer 1

when I need things to happen on a given moment, I tend (depending on the language I'm working on that moment) to either pass a promise or a callback ... to make things easier, why don't you simply pass a callback?

function initializeClock(id, endtime, cbTimeEnded) { 

    ...

    if(t.total === 0) {
        clearInterval(timeinterval);
        if(cbTimeEnded) cbTimeEnded(); // only call the callback if exists
    }
}

and then

...
initializeClock('clockdiv', deadline, function() {
    // time reached the end, you can do whatever you want...
    console.log('done');
});