Adding and customizing CaptchaWidget

Nowadays, on the Internet, if you leave a form without spam protection, you will get a ton of spam data entered in a short time. Yii includes a Captcha component that makes adding such protection a breeze. The only problem is that there is no systematic guide on how to use it.

In the following example, we will add Captcha protection to a simple form.

Getting ready

1. Create a new application by using the Composer package manager, as described in the official guide at http://www.yiiframework.com/doc-2.0/guide-start-installation.html.

2. Create a form model, @app/models/EmailForm.php, as follows:

   <?php
   namespace app\models;
   use yii\base\Model;
   class EmailForm extends Model
   {
       public $email;
       public function rules()
       {
           return [
               ['email', 'email']
           ];
       }
   }

3. Create a controller, @app/controllers/EmailController.php, as follows:

   <?php
   namespace app\controllers;
   use Yii;
   use yii\web\Controller;
   use app\models\EmailForm;
   class EmailController...