code: public function getClientOptions($model, $attribute)
      {
          $captcha = $this->createCaptchaAction();
          $code = $captcha->getVerifyCode(false);
          $hash = $captcha->generateValidationHash($this->caseSensitive ? $code : strtolower($code));
          $options = [
              'hash' => $hash,
              'hashKey' => 'yiiCaptcha/' . $captcha->getUniqueId(),
              'caseSensitive' => $this->caseSensitive,
              'message' => Yii::$app->getI18n()->format($this->message, [
                  'attribute' => $model->getAttributeLabel($attribute),
              ], Yii::$app->language),
          ];
          if ($this->skipOnEmpty) {
              $options['skipOnEmpty'] = 1;
          }
  
          return $options;
      }
docs: {@inheritdoc}