This is a small demo of webcam support in HTML exports for godot 4.3.
To build you will have to use the index.html in the Template directory as a custom shell, it contains the code to actually copy the frame data to your game.
JSHandler.gd then interprets that data into your img.
https://gitlab.com/greenfox/godot-html5-webcam Here's the source I used to create parts of this, it's for 3.x