我是 Laravel 的新手。這是我在 SmartpayS 控制器中的功能。我想在 iframe 中返回這個 url。$url = $item->nodeValue;function processSmartpaySPayment($paymentType = false, $totalAmount = 0, $currency = false, $payingUserId = false, $quoteId = false, $clubMembershipQuotationId = false)    {        $callBackUrl = 'smartpays-payment/response/'.$quoteId;        if (!empty($payingUserId)) {            $customerDetails = $this->customerRepo->getCustomerDetails($payingUserId);        } else {            return false;        }        $testString = $this->smartPaySRepo->createSmartpaySPayment($paymentType, env('ENTERPRISE_ID'), 'DE02', 'ECommerce',env('AUTH_TYPE'), $totalAmount, $customerDetails, $currency, $callBackUrl, $quoteId, $clubMembershipQuotationId, env('STORE_RESULT_PAGE') );        $dom = new \DOMDocument();        $dom->formatOutput = TRUE;        $dom->preserveWhiteSpace = FALSE;        $dom->loadXml($testString);        foreach ($dom->getElementsByTagName('redirectURL') as $item) {           $url = $item->nodeValue;        }        return redirect($url);}----------**********iframe is in the view.(paymentload.blade.php)*************<iframe src="<?php echo $url; ?>" width="600px" height ="800px" ></iframe>我試圖加載 iframe。但它說“未定義的變量：url” 幫助我從控制器函數返回視圖中的 iframe。