Node-RED iframe in a Node-RED template

There are possible issues with X-frame-options here, so the URL structure and requested resource are important.

Ex. "chromewebdata/:1 Refused to display 'https://www.google.com/' in a frame because it set 'X-Frame-Options' to 'sameorigin'."

Try something like this in your template node... I found you need to specify the entire URL, including device IP address. This is displaying my standard Node-RED dashboard (/node-red/ui) in an iframe at /node-red/ui/mobile.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Mobile UI</title>
</head>
<body>
    <div>
        <iframe style="width:500px; height:500px;" src="https://127.0.0.1:8443/node-red/ui/" frameborder="0" allowfullscreen></iframe>
    </div>
</body>
</html>