code: public function getClientOptions($model, $attribute)
      {
          $options = [];
          if ($this->requiredValue !== null) {
              $options['message'] = $this->formatMessage($this->message, [
                  'requiredValue' => $this->requiredValue,
              ]);
              $options['requiredValue'] = $this->requiredValue;
          } else {
              $options['message'] = $this->message;
          }
          if ($this->strict) {
              $options['strict'] = 1;
          }
  
          $options['message'] = $this->formatMessage($options['message'], [
              'attribute' => $model->getAttributeLabel($attribute),
          ]);
  
          return $options;
      }
docs: {@inheritdoc}