Solution 1:

In the last statement you are converting the duration to time which also considers the timezone. I assume that your timezone is +530, so 5 hours and 30 minutes gets added to 30 minutes. You can do as given below.

var eventTime= 1366549200; // Timestamp - Sun, 21 Apr 2013 13:00:00 GMT
var currentTime = 1366547400; // Timestamp - Sun, 21 Apr 2013 12:30:00 GMT
var diffTime = eventTime - currentTime;
var duration = moment.duration(diffTime*1000, 'milliseconds');
var interval = 1000;

setInterval(function(){
  duration = moment.duration(duration - interval, 'milliseconds');
    $('.countdown').text(duration.hours() + ":" + duration.minutes() + ":" + duration.seconds())
}, interval);

Solution 2:

Check out this plugin:

moment-countdown

moment-countdown is a tiny moment.js plugin that integrates with Countdown.js. The file is here.

How it works?

//from then until now
moment("1982-5-25").countdown().toString(); //=> '30 years, 10 months, 14 days, 1 hour, 8 minutes, and 14 seconds'

//accepts a moment, JS Date, or anything parsable by the Date constructor
moment("1955-8-21").countdown("1982-5-25").toString(); //=> '26 years, 9 months, and 4 days'

//also works with the args flipped, like diff()
moment("1982-5-25").countdown("1955-8-21").toString(); //=> '26 years, 9 months, and 4 days'

//accepts all of countdown's options
moment().countdown("1982-5-25", countdown.MONTHS|countdown.WEEKS, NaN, 2).toString(); //=> '370 months, and 2.01 weeks'

Solution 3:

Although I'm sure this won't be accepted as the answer to this very old question, I came here looking for a way to do this and this is how I solved the problem.

I created a demonstration here at codepen.io.

The Html:

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.13.0/moment.min.js" type="text/javascript"></script>
<script src="https://cdn.rawgit.com/mckamey/countdownjs/master/countdown.min.js" type="text/javascript"></script>
<script src="https://code.jquery.com/jquery-3.0.0.min.js" type="text/javascript"></script>
<div>
  The time is now: <span class="now"></span>, a timer will go off <span class="duration"></span> at <span class="then"></span>
</div>
<div class="difference">The timer is set to go off <span></span></div>
<div class="countdown"></div>

The Javascript:

var now = moment(); // new Date().getTime();
var then = moment().add(60, 'seconds'); // new Date(now + 60 * 1000);

$(".now").text(moment(now).format('h:mm:ss a'));
$(".then").text(moment(then).format('h:mm:ss a'));
$(".duration").text(moment(now).to(then));
(function timerLoop() {
  $(".difference > span").text(moment().to(then));
  $(".countdown").text(countdown(then).toString());
  requestAnimationFrame(timerLoop);
})();

Output:

The time is now: 5:29:35 pm, a timer will go off in a minute at 5:30:35 pm
The timer is set to go off in a minute
1 minute

Note: 2nd line above updates as per momentjs and 3rd line above updates as per countdownjs and all of this is animated at about ~60FPS because of requestAnimationFrame()


Code Snippet:

Alternatively you can just look at this code snippet:

var now = moment(); // new Date().getTime();
var then = moment().add(60, 'seconds'); // new Date(now + 60 * 1000);

$(".now").text(moment(now).format('h:mm:ss a'));
$(".then").text(moment(then).format('h:mm:ss a'));
$(".duration").text(moment(now).to(then));
(function timerLoop() {
  $(".difference > span").text(moment().to(then));
  $(".countdown").text(countdown(then).toString());
  requestAnimationFrame(timerLoop);
})();

// CountdownJS: http://countdownjs.org/
// Rawgit: http://rawgit.com/
// MomentJS: http://momentjs.com/
// jQuery: https://jquery.com/
// Light reading about the requestAnimationFrame pattern:
// http://www.paulirish.com/2011/requestanimationframe-for-smart-animating/
// https://css-tricks.com/using-requestanimationframe/
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.13.0/moment.min.js" type="text/javascript"></script>
<script src="https://cdn.rawgit.com/mckamey/countdownjs/master/countdown.min.js" type="text/javascript"></script>
<script src="https://code.jquery.com/jquery-3.0.0.min.js" type="text/javascript"></script>
<div>
  The time is now: <span class="now"></span>,
</div>
<div>
  a timer will go off <span class="duration"></span> at <span class="then"></span>
</div>
<div class="difference">The timer is set to go off <span></span></div>
<div class="countdown"></div>

Requirements:

  • CountdownJS: http://countdownjs.org/ (And Rawgit to be able to use countdownjs)
  • MomentJS: http://momentjs.com/
  • requestAnimationFrame() - use this for animation rather than setInterval().

Optional Requirements:

  • jQuery: https://jquery.com/

Additionally here is some light reading about the requestAnimationFrame() pattern:

  • http://www.paulirish.com/2011/requestanimationframe-for-smart-animating/
  • https://css-tricks.com/using-requestanimationframe/

I found the requestAnimationFrame() pattern to be much a more elegant solution than the setInterval() pattern.

Solution 4:

I thought I'd throw this out there too (no plugins). It counts down for 10 seconds into the future.

    var countDownDate = moment().add(10, 'seconds');

      var x = setInterval(function() {
        diff = countDownDate.diff(moment());
    
        if (diff <= 0) {
          clearInterval(x);
           // If the count down is finished, write some text 
          $('.countdown').text("EXPIRED");
        } else
          $('.countdown').text(moment.utc(diff).format("HH:mm:ss"));

      }, 1000);
<script src="https://momentjs.com/downloads/moment.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<div class="countdown"></div>