Countdown

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.22.2/moment.min.js"></script>
<div id="output">

</div>

JavaScript

function showCountdown(countSeconds)
{
   var duration = moment.duration({'seconds' : countSeconds});
   countStatus = moment.utc(duration.as('milliseconds')).format('HH:mm:ss');
   document.getElementById('output').innerHTML = "Count: " + countStatus;
}
var count = 10;
function countdown() {
// starts countdown
if (count == 0) {
// time is up
} else {
count--;
t = setTimeout(countdown, 1000);
showCountdown(count);
}
};

countdown();