Reload Select2 depending on DatePicker

Hi all,

I’m a little stuck…I have a _form.php with a datepicker and one Select2-Dropdown:

            Pjax::begin(['id' => 'pjax-employee-dropdown','enablePushState' => false]); 
           $data = ArrayHelper::map(Employee::getEmployee($model->fromDate),'id','name');               
            <?= $form->field($model, 'id')->widget(Select2::classname(),['id' => 'sel-pers-id',data' => $data,]) ?>            
            <?php Pjax::end() ?>
<?= $form->field($model, 'fromDate')->widget(DatePicker::classname(), [
                        'language' => 'de',
                        'options' => [
                            'id' => 'start-date-id',
                        'type' => DatePicker::TYPE_INPUT,
                        'pluginOptions' => [
                            'format' => '',
                            'todayHighlight' => true,
                            'autoclose' => true,
                        'pluginEvents' => [
                            'changeDate' => 'function(e) {
                                $.pjax.reload({container: "#pjax-employee-dropdown", async: false, timeout: false});                                
                    ]) ?>

What I’m trying todo: the Select2 should reload after the Date is changed and the function getEmployee() should be called with the now selected date. As you can see, I tried to reload via pjax, but how can I pass the actual value of the datepicker to the function?

Any help, tip, whatever would be highly appreciated, as I’m also lacking javascript skills…

Thanks in advance and I wish you all a happy and healthy new year.