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An easy and unobtrusive way to use jQuery's autocomplete with Rails 3
Ruby JavaScript HTML CSS
Latest commit 567c1e7 @bigtunacan bigtunacan Update
Added link to the new official repo location.

Project Moved

There has been some confusion around the naming as to where to find the Rails4 version of this gem due to the original naming. With the latest release I have taken the opportunity to address this by moving the official repo.

The official repo is now located at rails-jquery-autocomplete


Build Status Gem Version

An easy way to use jQuery's autocomplete with Rails 3.

Supports both ActiveRecord, mongoid, and MongoMapper.

Works with Formtastic and SimpleForm


You can find a detailed example on how to use this gem with ActiveRecord here.


You can find a detailed example on how to use this gem with MongoID here. (Same thing, different branch)

Before you start

Make sure your project is using jQuery-UI and the autocomplete widget before you continue.

You can find more info about that here:

I'd encourage you to understand how to use those 3 amazing tools before attempting to use this gem.


Include the gem on your Gemfile

gem 'rails3-jquery-autocomplete'

Install it

bundle install

Rails 3.0.x

Run the generator

rails generate autocomplete:install

And include autocomplete-rails.js on your layouts

javascript_include_tag "autocomplete-rails.js"

Upgrading from older versions

If you are upgrading from a previous version, run the generator after installing to replace the javascript file.

rails generate autocomplete:install

I'd recommend you do this every time you update to make sure you have the latest JS file.

Uncompressed Javascript file

If you want to make changes to the JS file, you can install the uncompressed version by running:

rails generate autocomplete:uncompressed

Rails 3.1.x and higher

Just add it to your app/assets/javascripts/application.js file

//= require jquery
//= require jquery_ujs
//= require jquery-ui
//= require autocomplete-rails


Model Example

Assuming you have a Brand model:

class Brand < ActiveRecord::Base

create_table :brand do |t|
  t.column :name, :string


To set up the required action on your controller, all you have to do is call it with the class name and the method as in the following example:

class ProductsController < Admin::BaseController
  autocomplete :brand, :name

This will create an action autocomplete_brand_name on your controller, don't forget to add it on your routes file

resources :products do
  get :autocomplete_brand_name, :on => :collection


:full => true

By default, the search starts from the beginning of the string you're searching for. If you want to do a full search, set the full parameter to true.

class ProductsController < Admin::BaseController
  autocomplete :brand, :name, :full => true

The following terms would match the query 'un':

  • Luna
  • Unacceptable
  • Rerun

:full => false (default behavior)

Only the following terms mould match the query 'un':

  • Unacceptable

:limit => 10 (default behavior)

By default your search result set is limited to the first 10 records. This can be overridden by specifying the limit option.


By default, your search will only return the required columns from the database needed to populate your form, namely id and the column you are searching (name, in the above example).

Passing an array of attributes/column names to this option will fetch and return the specified data.

class ProductsController < Admin::BaseController
  autocomplete :brand, :name, :extra_data => [:slogan]


If you want to display a different version of what you're looking for, you can use the :display_value option.

This options receives a method name as the parameter, and that method will be called on the instance when displaying the results.

class Brand < ActiveRecord::Base
  def funky_method

class ProductsController < Admin::BaseController
  autocomplete :brand, :name, :display_value => :funky_method

In the example above, you will search by name, but the autocomplete list will display the result of funky_method

This wouldn't really make much sense unless you use it with the "id_element" attribute. (See below)

Only the object's id and the column you are searching on will be returned in JSON, so if your display_value method requires another parameter, make sure to fetch it with the :extra_data option


Added option to support searching in hstore columns.

Pass a hash with two keys: :method and :key with values: the hstore field name and the key of the hstore to search.

e.g autocomplete :feature, :name, :hstore => {:method => 'name_translations', :key => 'en'}


Added option to use scopes. Pass scopes in an array. e.g :scopes => [:scope1, :scope2]


By default autocomplete uses method name as column name. Now it can be specified using column_name options :column_name => 'name'

json encoder

Autocomplete uses Yajl as JSON encoder/decoder, but you can specify your own

class ProductsController < Admin::BaseController
  autocomplete :brand, :name do |items|


On your view, all you have to do is include the attribute autocomplete on the text field using the url to the autocomplete action as the value.

form_for @product do |f|
  f.autocomplete_field :brand_name, autocomplete_brand_name_products_path

This will generate an HTML tag that looks like:

<input type="text" data-autocomplete="products/autocomplete_brand_name">

If you are not using a FormBuilder (form_for) or you just want to include an autocomplete field without the form, you can use the autocomplete_field_tag helper.

form_tag 'some/path'
  autocomplete_field_tag 'address', '', address_autocomplete_path, :size => 75

Multiple Values Separated by Delimiter

To generate an autocomplete input field that accepts multiple values separated by a given delimiter, add the 'data-delimiter' and :multiple options:

form_for @product do |f|
  f.autocomplete_field :brand_names, autocomplete_brand_name_products_path,
  'data-delimiter' => ',', :multiple => true

NOTE: Setting the :multiple option to true will result in the chosen values being submitted as an array. Leaving this option off will result in the values being passed as a single string, with the values separated by your chosen delimiter.

Automatically focus on the first autocompleted item

To have the first item be automatically focused on when the autocomplete menu is shown, add the 'data-auto-focus' option and set it to true.

form_for @product do |f|
    f.autocomplete_field :brand_names, autocomplete_brand_name_products_path,
    'data-auto-focus' => true

Now your autocomplete code is unobtrusive, Rails 3 style.

Getting the object id

If you need to use the id of the selected object, you can use the id_element attribute too:

f.autocomplete_field :brand_name, autocomplete_brand_name_products_path, :id_element => '#some_element'

This will update the field with id *#some_element with the id of the selected object. The value for this option can be any jQuery selector.

Changing destination element

If you need to change destination element where the autocomplete box will be appended to, you can use the :append_to option which generates a data-append-to HTML attribute that is used in jQuery autocomplete as append_to attribute.

The :append_to option accepts a string containing jQuery selector for destination element:

f.autocomplete_field :product_name, '/products/autocomplete_product_name', :append_to => "#product_modal"

The previous example would append the autocomplete box containing suggestions to element jQuery('#product_modal'). This is very useful on page where you use various z-indexes and you need to append the box to the topmost element, for example using modal window.

Sending extra search fields

If you want to send extra fields from your form to the search action, you can use the :fields options which generates a data-autocomplete-fields HTML attribute.

The :fields option accepts a hash where the keys represent the Ajax request parameter name and the values represent the jQuery selectors to retrieve the form elements to get the values:

f.autocomplete_field :product_name, '/products/autocomplete_product_name', :fields => {:brand_id => '#brand_element', :country => '#country_element'}

class ProductsController < Admin::BaseController
  def autocomplete_product_name
    term = params[:term]
    brand_id = params[:brand_id]
    country = params[:country]
    products = Product.where('brand = ? AND country = ? AND name LIKE ?', brand_id, country, "%#{term}%").order(:name).all
    render :json => { |product| {:id =>, :label =>, :value =>} }

Getting extra object data

If you need to extra data about the selected object, you can use the :update_elements HTML attribute.

The :update_elements attribute accepts a hash where the keys represent the object attribute/column data to use to update and the values are jQuery selectors to retrieve the HTML element to update:

f.autocomplete_field :brand_name, autocomplete_brand_name_products_path, :update_elements => {:id => '#id_element', :slogan => '#some_other_element'}

class ProductsController < Admin::BaseController
  autocomplete :brand, :name, :extra_data => [:slogan]

The previous example would fetch the extra attribute slogan and update jQuery('#some_other_element') with the slogan value.

Running custom code on selection

A javascript event named is fired on the input field when a value is selected from the autocomplete drop down. If you need to do something more complex than update fields with data, you can hook into this event, like so:

$('#my_autocomplete_field').bind('', function(event, data){
  /* Do something here */


If you are using Formtastic, you automatically get the autocompleted_input helper on semantic_form_for:

semantic_form_for @product do |f|
  f.input :brand_name, :as => :autocomplete, :url => autocomplete_brand_name_products_path

The only difference with the original helper is that you must specify the autocomplete url using the :url option.


If you want to use it with simple_form, all you have to do is use the :as option on the input and set the autocomplete path with the :url option.

simple_form_for @product do |form|
  form.input :name
  form.input :brand_name, :url => autocomplete_brand_name_products_path, :as => :autocomplete


I have created a step to test your autocomplete with Cucumber and Capybara, all you have to do is add the following lines to your env.rb file:

require 'cucumber/autocomplete'

Then you'll have access to the following step:

I choose "([^"]*)" in the autocomplete list

An example on how to use it:

Scenario: Autocomplete
  Given the following brands exists:
    | name  |
    | Alpha |
    | Beta  |
    | Gamma |
  And I go to the home page
  And I fill in "Brand name" with "al"
  And I choose "Alpha" in the autocomplete list
  Then the "Brand name" field should contain "Alpha"

I have only tested this using Capybara, no idea if it works with something else, to see it in action, check the example app.


I have created a helper to test your autocomplete with Steak and Capybara, all you have to do is add the following lines to your acceptance_helper.rb file:

require 'steak/autocomplete'

Then you'll have access to the following helper:


An example on how to use it:

scenario "Autocomplete" do
  lambda do
    Brand.create! [
      {:name => "Alpha"},
      {:name => "Beta"},
      {:name => "Gamma"}
  end.should change(Brand, :count).by(3)

  visit home_page
  fill_in "Brand name", :with => "al"
  choose_autocomplete_result "Alpha"
  find_field("Brand name").value.should include("Alpha")

I have only tested this using Capybara, no idea if it works with something else.


If you want to make changes to the gem, first install bundler 1.0.0:

gem install bundler

And then, install all your dependencies:

bundle install

Running the test suite

You need to have an instance of MongoDB running on your computer or all the mongo tests will fail miserably.

To run all the tests once, simply use

rake test

while you're developing, it is recommended that you run

bundle exec guard

to have the relevant test run every time you save a file.

Integration tests

If you make changes or add features to the jQuery part, please make sure you write a cucumber test for it.

You can find an example Rails app on the integration folder.

You can run the integration tests with the cucumber command while on the integration folder:

cd integration
rake db:migrate

Where to test what

If you're making or tweaking a plugin (such as the formtastic plugin or simple_form plugin), check out the simple_form_plugin_test for an example of how to test it as part of the main rake test run. Historically, plugins like these had been tested (shoddily) as part of the integration tests. Feel free to remove them from the integration suite and move them into the main suite. Your tests will run much faster, and there will be less likelihood of your feature breaking in the future. Thanks!

Thanks to

Everyone on this list

About the Author

Crowd Interactive is an American web design and development company that happens to work in Colima, Mexico. We specialize in building and growing online retail stores. We don’t work with everyone – just companies we believe in. Call us today to see if there’s a fit. Find more info here!

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