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;
}
}