Debouncing Window Scroll events with requestAnimationFrame #jquery. Source: http://www.html5rocks.com/en/tutorials/speed/animations/

gistfile1.coffee

jQuery.request_scroll = (callback) ->
  
  ###
  Callback for our scroll event - just
  keeps a track on the last scroll value
  ###
  onScroll = ->
    lastScrollY = window.scrollY
    requestTick()

  ###
  Calls rAF if it's not already
  been done already
  ###
  requestTick = ->
    unless ticking
      requestAnimFrame update
      ticking = true

  ###
  Our animation callback
  ###
  update = ->
    callback lastScrollY  
    # allow further rAFs to be called
    ticking = false

  lastScrollY = 0
  ticking = false

  # only listen for scroll events
  window.addEventListener "scroll", onScroll, false

  # shim layer with setTimeout fallback
  requestAnimFrame = (->
    window.requestAnimationFrame or
    window.webkitRequestAnimationFrame or
    window.mozRequestAnimationFrame or
    window.oRequestAnimationFrame or 
    window.msRequestAnimationFrame or 
    (timeout_callback) ->
      window.setTimeout timeout_callback, 1000 / 60
  )()