fake event for on iphone scroll end

scrollend.coffee

# this should be x-browser check
_raf = window.requestAnimationFrame

isScrolling = (fn) ->
  pageY = window.pageYOffset
  _checker = ->
    unless (fn(pageY != window.pageYOffset) is false)
      pageY = window.pageYOffset
      _raf(_checker)
  _raf(_checker)
  return _checker
  
$window = $(window)
onscrollend = (handler) ->
  timeout = null
  $window.on 'scroll.end', ->
    # throttle the function since we know
    # that scroll won't end while we're scrolling.
    # this will introduce delay so could be removed
    clearTimeout(timeout)
    timeout = setTimeout(->
      isScrolling((changed) ->
        return if changed
        # push to bottom of the stack
        # to be sure that scroll rendering has finished
        setTimeout(handler, 0)
        $window.off 'scroll.end'
        return false
      )
    , 100)
    
# usage
onscrollend = ->
  $('#element').show()