Rails 3 Client Side Validations
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Rails 3 Client Side Validations

Client Side Validations made easy for your Rails 3 applications!

In addition to this README please checkout the wiki

Project Goals

  1. Follow the best practices for client side validations written up by Luke Wroblewski
  2. Automatically extract and apply validation rules defined on the server to the client.
  3. In the cases where a server-side validation rule would not work on the client (i.e. conditional callbacks like :if, :unless) then do not attempt client side validations. Fall back to the server side validation.
  4. The client side validation error rendering should be indistinguishable from the server side validation error rendering.
  5. Wide browser compliancy. I've tested with IE8, seems to work OK.
  6. Work with any ActiveModel::Validations based model
  7. Validate nested fields
  8. Support custom validations
  9. Support custom FormBuilders like SimpleForm and Formtastic


Include Client Side Validations in your Gemfile

gem 'client_side_validations', '3.0.0.alpha.5'

Then run the install generator

rails g client_side_validations:install

This will install two files:



Always be sure to run

rails g client_side_validations:install

After upgrading Client Side Validations. There is a good chance that the client-side-validations.js file has changed.


Client Side Validations requires jQuery.

Include the client-side-validations.js file in your layout

<%= javascript_include_tag 'jquery', 'client-side-validations'-%>

Turn on the validations for each form_for

<%= form_for @book, :validate => true do |book| -%>

Nested fields automatically inherit the :validate value. If you want to turn it off just pass :validate => false to fields_for

<%= book.fields_for :pages, :validate => false do |page| -%>


The initializer includes a commented out ActionView::Base.field_error_proc. Uncomment this to render your error messages inline with the input fields.

I recommend you not use a solution similar to error_messages_for. Client Side Validations is never going to support rendering these type of error messages. If you want to maintain consistency between the client side rendered validation error messages and the server side rendered validation error messages please use what is in config/initializers/client_side_validations.rb


Client Side Validations supports SimeplForm. However, there is a load order issue. The ClientSideValidation gem must be required before the SimpleForm gem.

Other than that, everything else should work as normal.

By default the latest version of SimpleForm will attach HTML5 Form Validators. Client Side Validations will turn off the HTML5 Form Validators if a given form is told to use Client Side Validations.


Client Side Validations supports Formtastic. However, there is a load order issue. The ClientSideValidation gem must be required before the Formtastic gem.

Other than that, everything else should work as normal.


Brian Cardarella © 2011


Licensed under the MIT license