Some thoughts on a timestamp to countdown. depends on moment.js and jquery

app.coffee

class App
  constructor: ->
    $('.fullscreen').click @fullscreen
    $('#display').click -> $(@).hide()
    @started = true
    @loop()
  
  fullscreen: ->
    $('#display').html $(@).parent().html()
    $('#display').show()
    false

  dhm: (total)->
    cd = 24 * 60 * 60 * 1000
    ch = 60 * 60 * 1000
    cm = 60 * 1000
    days = Math.floor total / cd
    days_in_ms = days * cd
    hours = '0' + Math.floor (total - days_in_ms) / ch
    hours_in_ms = hours * ch
    mins = '0' + Math.floor (total - days_in_ms - hours_in_ms) / cm
    mins_in_ms = mins * cm
    secs = '0' + Math.round (total - days_in_ms - hours_in_ms - mins_in_ms) / 1000
    "#{days} : #{hours.substr(-2)} : #{mins.substr(-2)} : #{secs.substr(-2)}"

  loop: =>
    $('p.timer').each (index,element)=>
      target = moment.unix($(element).data('timestamp'))
      now = moment()
      $(element).html @dhm(target.diff(now))
    setTimeout(@loop, 100) if @started
$ ->
  window.app = new App()