is it possible to have qr reader on landing page?

I'm trying to build this landing page (triggered on connecting to a router) that has a form and to finalize the login process user need to scan a qr code given by the receptionist.

I followed this tutorial and the web page version successfully opens the camera app on a phone, take picture of the qr, upload it to the html and decode it using the js attached to it.

However upon mounting it on an actual landing page, the js execution seem to get stuck, couldn't even open the camera app.

Is there any significant differences between opening the html using browser and landing page that caused the js to fail?

Thanks in advance for any pointers.