gistfile1.coffee

window.History.Adapter.bind window, 'statechange', ->
    State = window.History.getState()
    window.History.log State.data, State.title, State.url

    if State.data.content?
      $('.product-page').html(State.data.content)

  dimensions = ":input[name='size_id'], :input[name='color_id'], :input[name='config_id']"

  window.History.replaceState { content: $('.product-page').html() }, null, window.location

  $(document).on 'change', dimensions, (event) ->

    input = $(this)
    form  = input.closest('form')

    values = {}

    $(dimensions).each (index) ->
      values[$(this).attr('id')] = $(this).val()

    $.fancybox.showLoading()

    xhr = $.post form.data('uri'), $(dimensions).serialize()
    xhr.done (data) ->
      newLocation = xhr.getResponseHeader 'Location'
      if newLocation?
        window.History.pushState { content: data }, null, newLocation
    xhr.always ->
      $.fancybox.hideLoading()