Question: Is there any way I can use the [moment.js](http://momentjs.com/) `format` method on duration objects? I can't find it anywhere in the docs and it doesn't seen to be an attribute on duration objects.

I'd like to be able to do something like:

```
var diff = moment(end).unix() - moment(start).unix();
moment.duration(diff).format('hh:mm:ss')

```

Also, if there are any other libraries which can easily accommodate this sort of functionality, I'd be interested in recommendations.

Thanks!

Answer: 
Use this line of code: 

```
moment.utc(moment.duration(4500, "seconds").asMilliseconds()).format("HH:mm:ss")

```
How about native javascript?

```
var formatTime = function(integer) {
    if(integer < 10) {
        return "0" + integer; 
    } else {
        return integer;
    }
}

function getDuration(ms) {
    var s1 = Math.floor(ms/1000);
    var s2 = s1%60;
    var m1 = Math.floor(s1/60);
    var m2 = m1%60;
    var h1 = Math.floor(m1/60);
    var string = formatTime(h1) +":" + formatTime(m2) + ":" + formatTime(s2);
    return string;
}

```