I recently asked the same thing.
It turns out it's an engine limitation due to requiring browser rendering engines which implement vsync, so the game runs at whatever speed the display refresh is at.
So for the meantime, cannot be done.
Basically just know the limits, when you make bigger games, the CPU becomes the bottleneck as its processing all your JS code 60 times per second. Optimize, and more optimizations!
How I approached my game is to limit cpuutilization to ~50% max (it measures CPU usage for the main game logic thread, single threaded bound). On my Intel i5-3570K, that means I am reaching 50% of the main thread. I can push it higher, going to 99% and the game starts to slow down. But 50% is a good target, because it means other CPUs that are much weaker, will be capable of sustaining 60 fps. I ended up with players on C2D PCs from 2006 with crap Intel graphics able to run the game fluid.