invoke = (f, start, interval, end) ->

  start = 0  unless start

  if arguments.length <= 2

    setTimeout f, start

    undefined

  else

    repeat = ->

      h = setInterval(f, interval)

      if end

        setTimeout (->

          clearInterval h

        ), end

    setTimeout repeat, start

    undefined

​

i = 0

writeNumber = ->

  document.writeln(i++)

​

invoke(writeNumber,1000)

invoke(writeNumber,1000,2000)

invoke(writeNumber,1000,2000,6000)