in ui/js/app.js [430:439]
$('#dp5').datepicker().on('changeDate', function (ev) {
if (ev.date.valueOf() < startDate.valueOf()) {
$('#alert').show().find('strong').text('The end date can not be less then the start date');
} else {
$('#alert').hide();
endDate = new Date(ev.date);
$('#endDate').text($('#dp5').data('date'));
}
$('#dp5').datepicker('hide');
});