Moment.JS return the current timestamp
http://stackoverflow.com/questions/25734743/moment-js-return-the-current-timestamp/25734809#25734809
HTML
<script src="//cdnjs.cloudflare.com/ajax/libs/moment.js/2.8.2/moment.min.js"></script>
JavaScript
var m = moment();
var a = m.unix();
setTimeout(function () {
console.log(m.unix() - a);
}, 1000);