What technology must I use to build an app that runs on web browser(mobile and desktop) and uses device camera?

Im a beginner coder that is trying to make an app that runs on Mobile and desktop web browsers that can access and display the live camera preview in a window inside the browser. OpenCV will be used to do some operations such as optical tracking and such. Ive done this on desktop and android platforms using the Unity3d engine and it works quite well with around 60fps.Now I would like to build the same app except it must run inside a browser on mobile and desktop devices.

What technology should I use to build something like this since unity3d is not good for building apps that run on mobile browsers.

Thanks for any suggestions.

Ive tried making a webgl build from Unity of the same project and it works at about 20fps on desktop browser, however it says Unity does not support mobile web browsers when I tried to run it on a mobile web browser.