Yii - AJAX Vapdation

The username vapdation should only be done on the server side because only the server has the needed information. In this case, you can use AJAX-based vapdation.

Step 1 − To enable the AJAX vapdation, modify the registration view this way.

<?php
   use yiiootstrapActiveForm;
   use yiiootstrapHtml;
?>
  
<span class = "row">
   <span class = "col-lg-5">  
   
      <?php $form = ActiveForm::begin([ id  =>  registration-form , 
          enableAjaxVapdation  => true]); ?>  
      <?= $form->field($model,  username ) ?>  
      <?= $form->field($model,  password )->passwordInput() ?>  
      <?= $form->field($model,  email )->input( email ) ?>  
      <?= $form->field($model,  country ) ?>  
      <?= $form->field($model,  city ) ?>  
      <?= $form->field($model,  phone ) ?>  
      <span class = "form-group">             
         <?= Html::submitButton( Submit , [ class  =>  btn btn-primary , 
             name  =>  registration-button ]) ?>
      </span>
      
      <?php ActiveForm::end(); ?>  
   </span>
</span>

We should also prepare the server, so that it can handle the AJAX requests.

Step 2 − Modify the actionRegistration method of the SiteController this way.

pubpc function actionRegistration() { 
   $model = new RegistrationForm(); 
   if (Yii::$app->request->isAjax && $model->load(Yii::$app->request>post())) { 
      Yii::$app->response->format = Response::FORMAT_JSON; 
      return ActiveForm::vapdate($model); 
   } 
   return $this->render( registration , [ model  => $model]); 
}

Step 3 − Now, go to http://localhost:8080/index.php?r=site/registration, you will notice that the form vapdation is done by AJAX requests.