Note: I am well aware of the fact the WebGL is not fully supported on mobile platform. Questions: What is the best way to add touch controls (swipe, pinch) to a WebGL game played on a mobile device? What about a laptop touch screen? It should work the same, isn't it? Thanks in advance.
If you are using Unity UI, the touch controls should just work (assuming standard input settings in your project) I've been building WebGL1.0 for iPad / Safari. Buttons and swipes are all working.
I have no problems with UI. I have a scene with orbit camera rotating around 3D objects. I'd like to be able to rotate them with swipe and zoom with pinch.
Use the EventSystem appropriate for your game. It sounds like it's a 3D game, so use a combination of StandaloneInputModule + GraphicRaycaster for your UI and PhysicsRaycaster for your 3D objects.