const a = moment("09:00","HH:mm", true).format();const b = moment("11:00","HH:mm", true).format();var c = moment(b).diff(a,"minutes", true);var d = moment().hours(0).minutes(c).format('HH:mm');alert(d);<script src="http://cdnjs.cloudflare.com/ajax/libs/moment.js/2.2.1/moment.min.js"></script>