request->getQueryParam(self::REFRESH_GET_VAR) !== null) { // AJAX request for regenerating code $code = $this->getVerifyCode(true); Yii::$app->response->format = Response::FORMAT_JSON; return [ 'hash1' => $this->generateValidationHash($code), 'hash2' => $this->generateValidationHash(strtolower($code)), // we add a random 'v' parameter so that FireFox can refresh the image // when src attribute of image tag is changed 'url' => Url::to([$this->id, 'v' => uniqid('', true)], true), ]; } $this->setHttpHeaders(); Yii::$app->response->format = Response::FORMAT_RAW; return $this->renderImage($this->getVerifyCode()); } }