implement qr code scanner in my flask project

Hi, I have to implement a javascript library to capture the content of a qr code, this one that I am attaching works very well, but I would need to make some small changes such as automatically calling "Request camera Permission" without having to click on the appropriate button, edc set the rear camera by default

https://github.com/mebjas/html5-qrcode/blob/master/examples/html5/index.html