POST数据时400错误

public function init(){
    $this->enableCsrfValidation = false;
}

<input name="_csrf" type="hidden" id="_csrf" value="<?= Yii::$app->request->csrfToken ?>">

var csrfToken = $('meta[name="csrf-token"]').attr("content");
$.ajax({
  type: 'POST',
  url: url,
  data: {_csrf:csrfToken},
  success: success,
  dataType: dataType
});