<?= $form->field($model, 'ID_region')->dropDownList($arrReg,[
        'prompt'=>'Область',
    'onchange'=>'$.post("/enrollee/area/lists?ID='.'"+$(this).val(),function (data){
     $("select#enrollee-id_area").html(data);
     });' and  '$.post("/enrollee/city/lists?ID='.'"+$(this).val(),function (data){
     $("select#enrollee-id_city").html(data);
     });' ,

]) ?>