Chosen is a library for making long, unwieldy select boxes more user friendly.

The chosen-rails gem integrates the Chosen with the Rails asset pipeline.

Include chosen-rails in Gemefile

gem 'chosen-rails'

Then run bundle install

Add to your app/assets/javascripts/application.js if use with jQuery

//= require chosen-jquery

Or with Prototype

//= require chosen-prototype

Add to your app/assets/stylesheets/application.css

*= require chosen

Add to one coffee script file, like scaffold.js.coffee

$ ->
  # enable chosen js
  $('.chosen-select').chosen
    allow_single_deselect: true
    no_results_text: 'No results matched'
    width: '200px'

Notice: width option is required since Chosen 0.9.15.

And this file must be included in application.js

//= require chosen-jquery
//= require scaffold

Also add the class to your form field

<%= f.select :author,
  User.all.map { |u| [u.name, u.id] },
               { include_blank: true },
               { class: 'chosen-select' }
%>

If you use simple form as form builder

<%= f.association :author, 
                  collection: User.all,
                  include_blank: true,
                  input_html: { class: 'chosen-select' }
%>

Since version 0.13.0, non-digested assets of chosen-rails will simply be copied from digested assets.

chosen-rails provides RSpec feature helper methods that allow users to select or unselect options from both single and multiple chosen elements. Add the following to your spec/rails_helper.rb (or spec/spec_helper.rb):

require 'chosen-rails/rspec'

This automatically configures RSpec by adding:

RSpec.configure do |config|
  config.include Chosen::Rspec::FeatureHelpers, type: :feature
end

Configuration includes two additional methods for all type: :feature specs:

chosen_select(value, options = {})
chosen_unselect(value, options = {})

Both methods require from: '...' inside the options hash that is either a CSS selector or a field's label (requires the for attribute on the label!).

To handle a single select:

chosen_select('Leo Tolstoy', from: 'Author')
chosen_unselect('Leo Tolstoy', from: '#author')
chosen_select('Fyodor Dostoyevsky', from: '#author')

To handle a multiple select:

chosen_select('Leo Tolstoy', 'Fyodor Dostoyevsky', 'Anton Chekhov', from: 'Authors')
# or, by single value:
chosen_select('Leo Tolstoy', from: '#authors')

chosen_unselect('Fyodor Dostoyevsky', ' Anton Chekhov', from: 'Authors')
# or, by single value:
chosen_unselect('Leo Tolstoy', from: '#authors')

Maintain chosen-rails gem with Rake commands.

Update origin chosen source files.

rake update-chosen

Publish gem.

rake release

use MIT license.