public function actionCounties()
 {
     $c = Yii::$app->request->post('city');
     if (empty($c) || $c <= 0) {
         throw new BadRequestHttpException();
     }
     $counties = Area::findByParent($c);
     foreach ($counties as $county) {
         echo '<option value="' . $county['id'] . '">' . $county['name'] . '</option>' . PHP_EOL;
     }
 }