A Very Simple - Timezone Agnostic - Countdown Script.

countdown.coffee

class window.Countdown
  constructor: (ends_at, custom_callbacks) ->
    now = new Date
    end = new Date(Number(ends_at) * 1000)

    default_callbacks =
      tick: ->
      complete: ->

    @callbacks  = $.extend(default_callbacks, custom_callbacks)
    @difference = Math.ceil((end - now) / 1000)
    @start()

  start: ->
    @interval_id = window.setInterval (=>
      @tick()
    ), 1000

  tick: ->
    if @difference > 0
      @difference--
      @callbacks.tick
        seconds:  @pad(@difference % 60)
        minutes:  @pad(Math.floor(@difference / 60) % 60)
        hours:    Math.floor(@difference / 60 / 60) % 24
    else
      @stop()

  pad: (number) ->
    "0#{number}".slice(-2)

  complete: (callback) ->
    @stop()
    @callbacks.complete()

  stop: ->
    window.clearInterval @interval_id

#######################################################################################

$ ->
  countdown = new Countdown "1351090738", # winnable_at.to_i
    tick: (date) ->
      $('#countdown .timer .hours').text(date.hours)
      $('#countdown .timer .minutes').text(date.minutes)
      $('#countdown .timer .seconds').text(date.seconds)

    complete: ->
      # AJAX Request for results. Retry on 403.
      console?.log? 'Countdown Complete'

countdown.js

window.Countdown = (function() {

  function Countdown(ends_at, custom_callbacks) {
    var default_callbacks, end, now;
    now = new Date;
    end = new Date(Number(ends_at) * 1000);
    default_callbacks = {
      tick: function() {},
      complete: function() {}
    };
    this.callbacks = $.extend(default_callbacks, custom_callbacks);
    this.difference = Math.ceil((end - now) / 1000);
    this.start();
  }

  Countdown.prototype.start = function() {
    var _this = this;
    return this.interval_id = window.setInterval((function() {
      return _this.tick();
    }), 1000);
  };

  Countdown.prototype.tick = function() {
    if (this.difference > 0) {
      this.difference--;
      return this.callbacks.tick({
        seconds: this.pad(this.difference % 60),
        minutes: this.pad(Math.floor(this.difference / 60) % 60),
        hours: Math.floor(this.difference / 60 / 60) % 24
      });
    } else {
      return this.stop();
    }
  };

  Countdown.prototype.pad = function(number) {
    return ("0" + number).slice(-2);
  };

  Countdown.prototype.complete = function(callback) {
    this.stop();
    return this.callbacks.complete();
  };

  Countdown.prototype.stop = function() {
    return window.clearInterval(this.interval_id);
  };

  return Countdown;

})();

$(function() {
  var countdown;
  return countdown = new Countdown("1351090738", {
    tick: function(date) {
      $('#countdown .timer .hours').text(date.hours);
      $('#countdown .timer .minutes').text(date.minutes);
      return $('#countdown .timer .seconds').text(date.seconds);
    },
    complete: function() {
      return typeof console !== "undefined" && console !== null ? typeof console.log === "function" ? console.log('Countdown Complete') : void 0 : void 0;
    }
  });
});