解决yii2.0 api post报错问题

Bad Request (#400): Unable to verify your date submission.   （无法验证提交的数据）

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

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

$.ajax({
             url: 'demo.php',//发送验证码的url
             type: 'post',
             data: {
                 _csrf:"<?=Yii::$app->request->csrfToken?>",
                 mobile:123
             },
             success: function(){
                     alert(&#39;发送成功&#39;);
             },
             error: function(){
                 alert(&#39;发送失败&#39;);
                 return false;
             }
         })