var startDate = "", endDate = "";
$('#dateTimeRange').daterangepicker({
"startDate": "09/30/2015",
"endDate": "10/06/2015"
}, function(start, end, label) {
startDate = start.format('YYYY-MM-DD');
endDate = end.format('YYYY-MM-DD');
});
var dateDiff = Math.abs(startDate.getTime() - endDate.getTime()) / 3600000;
-KR