gistfile1.js

// Note that the track_changes function indicated in the callback is part of
// a custom change tracking solution that is called in the onchange event
// of extended form elements.

var date_picker_field_id = 'some-dom-id';
var date_picker_field = $(date_picker_field_id);

form_elements = {};
form_elements[date_picker_field_id] = '%Y-%m-%d';

datePickerController.createDatePicker({
	formElements: form_elements,
	callbackFunctions: { 'dateset': [date_picker_field.track_changes.bind(date_picker_field)] }
});