Well, I've reported an issue about jitter movement on my ARPG game long time ago, then no one cares until this thread.
I know a way to get pure performance is about monitor resolution, besides you can resize browser window to small like 400 x 300, you get perfect 60 fps and smooth movement, there a 10% chance of getting spike lag in every tick due to GC.
Otherwise, the bigger canvas screen is upscaled to 1920 x 1080 it would cause jitter and frequently spike lags. So HTML5 is not perfect for gaming.