DependentFields makes it easy to hide or show dependent fields in forms based on select or checkbox values.

1. Add gem 'dependent-fields-rails' to your Gemfile.

2. Run bundle install.

3. Add //= require dependent-fields to your Javascript manifest file (usually found at app/assets/javascripts/application.js).

4. Bind events, for example with jquery:

    $(document).ready(function() {
        DependentFields.bind()
    });
   

5. Restart your server and everything should be set up. See Usage below on how to declare your dependent fields in views.

Be sure to include underscorejs and jquery in your page.

Dependent Fields may depend on select or checkbox input elements. You have to surround your dependent fields with a div with class js-dependent-fields.

The examples below are written in the slim template language with simple_form. But you can use dependent-fields with every other template language out there.

Note the data attributes on the js-dependent-fields div.

= simple_form_for(@filing) do
    = f.input :registration_office, collection: ['habm', 'dpma']

    .js-dependent-fields[data-select-id='filing_registration_office' data-option-value='habm']
        = f.input :language, collection: ['english', 'german']

The language selector will only be shown if the user selects 'habm' in the registration office.

You can also specify multiple option values by seperating them with |. For example: data-option-value='habm|dpma'

Note the data attributes on the js-dependent-fields div.

= simple_form_for(@filing) do
    = f.input :priority_enabled

    .js-dependent-fields[data-checkbox-id='filing_priority_enabled' data-checkbox-value='true']
      = f.input :priority_date
      = f.input :priority_filing_nr

The date and filing_nr fields will only be shown if the user checks the priority_enabled field.

Relevant radio inputs are selected by name and not by id, because radio inputs in the same group have different ids but the same name. Note the data attributes on the js-dependent-fields div.

= simple_form_for(@filing) do
    = f.input :registration_office, collection: ['habm', 'dpma'], as: :radio_buttons

    .js-dependent-fields[data-radio-name='filing[registration_office]' data-radio-value='habm']
        = f.input :language, collection: ['english', 'german']

The language selector will only be shown if the user selects 'habm' in the registration office.

You can also specify multiple option values by seperating them with |. For example: data-radio-value='habm|dpma'

Add data-method='disable' to the js-dependent-fields div.

http://jsfiddle.net/mwhSt/

• make it compatible with rails4. thanks to mcbridejc for the pull request.
• fix an example in the README. thanks to michaelkeenan for the pull request.

• fix escaping of attribute names. thanks to nagyt234 for the pull request.