Tried it on my 2016 Macbook Pro. Has some performance issues, I don't know how many exactly, but I'd say I'm getting around 10 FPS or less.
Framerates are much better in the non-web version somehow: I suspect some unnecessary texture sampling ops are to blame, but I need to investigate.
Resizing the window to a smaller helps greatly improve the framerate, which tends to show that the bottleneck is in the fragment shaders.