in ui/js/app.js [420:429]
$('#dp4').datepicker().on('changeDate', function (ev) {
if (ev.date.valueOf() > endDate.valueOf()) {
$('#alert').show().find('strong').text('The start date can not be greater then the end date');
} else {
$('#alert').hide();
startDate = new Date(ev.date);
$('#startDate').text($('#dp4').data('date'));
}
$('#dp4').datepicker('hide');
});