Integrating chosen for tags with the ability to add (the coffeescript portion).

chosen.coffee

window.chosen_select =
  enable: ->
    $('.chosen-select').chosen
      allow_single_deselect: true
      no_results_text: 'No results found'
      width: '100%'

  add: (select, string) ->
    select.prepend($('<option selected="selected">', { value: string })
                  .text(string))
                  .trigger('chosen:updated')

$(document).ready ->
  chosen_select.enable()

$(document).on 'page:load', ->
  chosen_select.enable()

tags.coffee

create_tags =
  bind_buttons: ->
    $('#create_tag').on 'click', ->
      $('#tag_wrapper').slideToggle ->
        $('#create_tag_wrapper').slideToggle()

    $('#cancel_tag').on 'click', ->
      $('#tag_text_field').val('')
      $('#create_tag_wrapper').slideToggle ->
        $('#tag_wrapper').slideToggle()

    $('#add_tag').on 'click', ->
      chosen_select.add($('#tag_wrapper').find('select'), $('#tag_text_field').val())
      $('#tag_text_field').val('')
      $('#create_tag_wrapper').slideToggle ->
        $('#tag_wrapper').slideToggle()

$(document).ready ->
  create_tags.bind_buttons()

$(document).on 'page:load', ->
  create_tags.bind_buttons()