Some JS/Coffee Game dev gizmo out of http://nokarma.org/2011/02/02/javascript-game-development-the-game-loop/index.html

gameloop_fixedCycles.coffee

class Game
  constructor: ()->

  draw: ()->

  update: ()->

  run: (()=>
    skipTicks = 1000/@fps
    maxFrameSkip = 10
    nextGameTick = (new Date).getTime()
    ()=>
      loops = 0
      while (new Date).getTime() > nextGameTick && loops < maxFrameSkip
        @update()
        nextGameTick += skipTicks
        loops++
      @draw()
  )()

Game._intervalId = setInterval Game.run, 0