These depend on a 3D renderer, which you only get in WebGL. So it won't yet run everywhere. It's on the todo list, but it's likely to be a low priority for a while. Broader WebGL support would be a good motivator. I'm surprised to see that apparently not many games use WebGL shaders, presumably because of the patchy support, and they were very difficult to implement, so I don't want to do lots of hard work for a feature that isn't used much again.