moment.js testing

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/moment.js/2.2.1/moment.min.js"></script>
<div class="conthttp://jsfiddle.net/beebul/kwdo9yrj/49/#forkrols">
    <input type="text" style="width:300px" name="momentDurationHours" id="momentDurationHours" readonly="" />&nbsp; 
    <a href="#" id="show">Show Total duration</a>
</div>

JavaScript

$('#show').click(function () {
       var now  = "04/09/2013 15:00:00";
var then = "02/09/2013 14:20:30";

var ms = moment(now,"DD/MM/YYYY HH:mm:ss").diff(moment(then,"DD/MM/YYYY HH:mm:ss"));
var d = moment.duration(ms);
var s = Math.floor(d.asHours()) + moment.utc(ms).format(":mm:ss");
    });