In version 2.1.5
changeDate has been renamed to change.dp so changedate was not working for me
$("#datetimepicker").datetimepicker().on('change.dp', function (e) {
FillDate(new Date());
});
also needed to change css class from datepicker to datepicker-input
<div id='datetimepicker' class='datepicker-input input-group controls'>
<input id='txtStartDate' class='form-control' placeholder='Select datepicker' data-rule-required='true' data-format='MM-DD-YYYY' type='text' />
<span class='input-group-addon'>
<span class='icon-calendar' data-time-icon='icon-time' data-date-icon='icon-calendar'></span>
</span>
</div>
Date formate also works in capitals like this data-format='MM-DD-YYYY'
it might be helpful for someone it gave me really hard time :)