⚠️ This documentation is for the master branch, which targets Bootstrap v4. If you are using Bootstrap v3, refer to the stable legacy-2.7 branch.

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bootstrap_form

bootstrap_form is a Rails form builder that makes it super easy to integrate Bootstrap v4-style forms into your Rails application.

Requirements

Ruby 2.2.2+
Rails 5.0+ (Rails 5.1+ for bootstrap_form_with)
Bootstrap 4.0.0+

Installation

Add it to your Gemfile:

gem "bootstrap_form", ">= 4.1.0"

Then:

bundle

Then require the CSS in your application.css file:

/*
 *= require rails_bootstrap_forms
 */

Usage

To get started, just use the bootstrap_form_for helper. Here's an example:

<%= bootstrap_form_for(@user) do |f| %>
  <%= f.email_field :email %>
  <%= f.password_field :password %>
  <%= f.check_box :remember_me %>
  <%= f.submit "Log In" %>
<% end %>

This generates the following HTML:

<form accept-charset="UTF-8" action="/users" class="new_user" id="new_user" method="post">
  <div class="form-group">
    <label for="user_email">Email</label>
    <input class="form-control" id="user_email" name="user[email]" type="email">
  </div>
  <div class="form-group">
    <label for="user_password">Password</label>
    <input class="form-control" id="user_password" name="user[password]" type="password">
  </div>
  <div class="form-check">
    <input name="user[remember_me]" type="hidden" value="0">
    <input class="form-check-input" id="user_remember_me" name="user[remember_me]" type="checkbox" value="1">
    <label class="form-check-label" for="user_remember_me">Remember me</label>
  </div>
  <input class="btn btn-secondary" name="commit" type="submit" value="Log In">
</form>

bootstrap_form_tag

If your form is not backed by a model, use the bootstrap_form_tag. Usage of this helper is the same as bootstrap_form_for, except no model object is passed in as the first argument. Here's an example:

<%= bootstrap_form_tag url: '/subscribe' do |f| %>
  <%= f.email_field :email, value: 'name@example.com' %>
  <%= f.submit %>
<% end %>

`bootstrap_form_with` (Rails 5.1+)

Note that form_with in Rails 5.1 does not add IDs to form elements and labels by default, which are both important to Bootstrap markup. This behavior is corrected in Rails 5.2.

To get started, just use the bootstrap_form_with helper in place of form_with. Here's an example:

<%= bootstrap_form_with(model: @user, local: true) do |f| %>
  <%= f.email_field :email %>
  <%= f.password_field :password %>
  <%= f.check_box :remember_me %>
  <%= f.submit "Log In" %>
<% end %>

This generates:

<form role="form" action="/users" accept-charset="UTF-8" method="post">
  <input name="utf8" type="hidden" value="&#x2713;" />
  <div class="form-group">
    <label class="required" for="user_email">Email</label>
    <input class="form-control" type="email" value="steve@example.com" name="user[email]" />
  </div>
  <div class="form-group">
    <label for="user_password">Password</label>
    <input class="form-control" type="password" name="user[password]" />
    <small class="form-text text-muted">A good password should be at least six characters long</small>
  </div>
  <div class="form-check">
    <input name="user[remember_me]" type="hidden" value="0">
    <input class="form-check-input" id="user_remember_me" name="user[remember_me]" type="checkbox" value="1">
    <label class="form-check-label" for="user_remember_me">Remember me</label>
  </div>
  <input type="submit" name="commit" value="Log In" class="btn btn-secondary" data-disable-with="Log In" />
</form>

bootstrap_form_with supports both the model: and url: use cases in form_with.

form_with has some important differences compared to form_for and form_tag, and these differences apply to bootstrap_form_with. A good summary of the differences can be found at: https://m.patrikonrails.com/rails-5-1s-form-with-vs-old-form-helpers-3a5f72a8c78a, or in the Rails documentation.

Future Compatibility

The Rails team has suggested that form_for and form_tag may be deprecated and then removed in future versions of Rails. bootstrap_form will continue to support bootstrap_form_for and bootstrap_form_tag as long as Rails supports form_for and form_tag.

Form Helpers

This gem wraps the following Rails form helpers:

check_box
collection_check_boxes
collection_select
color_field
date_field
date_select
datetime_field
datetime_local_field
datetime_select
email_field
file_field
grouped_collection_select
hidden_field (not wrapped, but supported)
month_field
number_field
password_field
phone_field
radio_button
collection_radio_buttons
range_field
rich_text_area (Rails 6+)
search_field
select
telephone_field
text_area
text_field
time_field
time_select
time_zone_select
url_field
week_field
submit
button

These helpers accept the same options as the standard Rails form helpers, with a few extra options:

Labels

Use the label option if you want to specify the field's label text:

<%= f.password_field :password_confirmation, label: "Confirm Password" %>

To hide a label, use the hide_label: true option. This adds the sr-only class, which keeps your labels accessible to those using screen readers.

<%= f.text_area :comment, hide_label: true, placeholder: "Leave a comment..." %>

To add custom classes to the field's label:

<%= f.text_field :email, label_class: "custom-class" %>

Or you can add the label as input placeholder instead (this automatically hides the label):

<%= f.text_field :email, label_as_placeholder: true %>

Required Fields

A label that is associated with a required field is automatically annotated with a required CSS class. You are free to add any appropriate CSS to style required fields as desired. One example would be to automatically add an asterisk to the end of the label:

label.required:after {
  content:" *";
}

The label required class is determined based on the definition of a presence validator with the associated model attribute. Presently this is one of: ActiveRecord::Validations::PresenceValidator or ActiveModel::Validations::PresenceValidator.

In cases where this behavior is undesirable, use the required option to force the class to be present or absent:

<%= f.password_field :login, label: "New Username", required: true %>
<%= f.password_field :password, label: "New Password", required: false %>

Input Elements / Controls

To specify the class of the generated input tag, use the control_class option:

<%= f.text_field :email, control_class: "custom-class" %>

Help Text

To add help text, use the help option:

<%= f.password_field :password, help: "Must be at least 6 characters long" %>

This gem is also aware of help messages in locale translation files (i18n):

en:
  activerecord:
    help:
      user:
        password: "A good password should be at least six characters long"

Help translations containing HTML should follow the convention of appending _html to the name:

en:
  activerecord:
    help:
      user:
        password_html: "A <strong>good</strong> password should be at least six characters long"

If your model name has multiple words (like SuperUser), the key on the translation file should be underscored (super_user).

You can override help translations for a particular field by passing the help option or turn them off completely by passing help: false.

Prepending and Appending Inputs

You can pass prepend and/or append options to input fields:

<%= f.text_field :price, prepend: "$", append: ".00" %>

You can also prepend and append buttons. Note: The buttons must contain the btn class to generate the correct markup.

<%= f.text_field :search, append: link_to("Go", "#", class: "btn btn-secondary") %>

To add a class to the input group wrapper, use the :input_group_class option.

<%= f.email_field :email, append: f.primary('Subscribe'), input_group_class: 'input-group-lg' %>

Additional Form Group Attributes

If you want to add an additional css class or any other attribute to the form group div, you can use the wrapper: { class: 'additional-class', data: { foo: 'bar' } } option.

<%= f.text_field :name, wrapper: { class: 'has-warning', data: { foo: 'bar' } } %>

Which produces the following output:

<div class="form-group has-warning" data-foo="bar">
  <label class="form-control-label" for="user_name">Id</label>
  <input class="form-control" id="user_name" name="user[name]" type="text">
</div>

You still can use wrapper_class option to set only a css class. This is just a short form of wrapper: { class: 'additional-class' }.

Suppressing the Form Group Altogether

You may have want to define your own form group div around a field. To do so, add the option wrapper: false to the input field. For example:

f.form_group :user do
  f.email_field :email, wrapper: false
end

Note that Bootstrap relies on the form group div to correctly format most fields, so if you use the wrapper: false option, you should provide your own form group div around the input field. You can write your own HTML, or use the form_group helper.

Selects

Our select helper accepts the same arguments as the default Rails helper. Here's an example of how you pass both options and html_options hashes:

<%= f.select :product, [["Apple", 1], ["Grape", 2]], { label: "Choose your favorite fruit:", wrapper: { class: 'has-warning', data: { foo: 'bar' } } }, { class: "selectpicker" } %>

Checkboxes and Radios

Checkboxes and radios should be placed inside of a form_group to render properly. The following example ensures that the entire form group will display an error if an associated validations fails:

<%= f.form_group :skill_level, label: { text: "Skill" }, help: "Optional Help Text" do %>
  <%= f.radio_button :skill_level, 0, label: "Novice", checked: true %>
  <%= f.radio_button :skill_level, 1, label: "Intermediate" %>
  <%= f.radio_button :skill_level, 2, label: "Advanced" %>
<% end %>

<%= f.form_group :terms do %>
  <%= f.check_box :terms, label: "I agree to the Terms of Service" %>
<% end %>

You can also create a checkbox using a block:

<%= f.form_group :terms, label: { text: "Optional Label" } do %>
  <%= f.check_box :terms do %>
    You need to check this box to accept our terms of service and privacy policy
  <% end %>
<% end %>

To display checkboxes and radios inline, pass the inline: true option:

<%= f.form_group :skill_level, label: { text: "Skill" } do %>
  <%= f.radio_button :skill_level, 0, label: "Novice", inline: true %>
  <%= f.radio_button :skill_level, 1, label: "Intermediate", inline: true %>
  <%= f.radio_button :skill_level, 2, label: "Advanced", inline: true %>
<% end %>

Check boxes and radio buttons are wrapped in a div.form-check. You can add classes to this div with the :wrapper_class option:

<%= f.radio_button :skill_level, 0, label: "Novice", inline: true, wrapper_class: "w-auto" %>

Switches

To render checkboxes as switches with Bootstrap 4.2+, add the proper wrapper class:

<%= f.check_box :remember_me, custom: true, wrapper_class: 'custom-switch' %>

Collections

bootstrap_form also provides helpers that automatically create the form_group and the radio_buttons or check_boxes for you:

<%= f.collection_radio_buttons :skill_level, Skill.all, :id, :name %>
<%= f.collection_check_boxes :skills, Skill.all, :id, :name %>

Collection methods accept these options:

:label: Customize the form_group's label
:hide_label: Pass true to hide the form_group's label
:help: Add a help span to the form_group
Other options will be forwarded to the radio_button/check_box method

Static Controls

You can create a static control like this:

<%= f.static_control :email %>

Here's the output for a horizontal layout:

<div class="form-group">
  <label class="col-sm-2 form-control-label" for="user_email">Email</label>
  <div class="col-sm-10">
    <input class="form-control-plaintext" id="user_email" name="user[email]" readonly="readonly" type="text" value="test@email.com"/>
  </div>
</div>

You can also create a static control that isn't based on a model attribute:

<%= f.static_control :field_name, label: "Custom Static Control" value: "Content Here" %>

field_name may be any name that isn't already used in the form. Note that you may get "unpermitted parameter" messages in your log file with this approach.

You can also create the static control the following way, if you don't need to get the value of the static control as a parameter when the form is submitted:

<%= f.static_control label: "Custom Static Control" value: "Content Here", name: nil %>

(If you neither provide a field name nor name: nil, the Rails code that submits the form will give a JavaScript error.)

Prior to version 4 of bootstrap_form, you could pass a block to the static_control method. The value of the block would be used for the content of the static "control". Bootstrap 4 actually creates and styles a disabled input field for static controls, so the value of the control has to be specified by the value: option. Passing a block to static_control no longer has any effect.

Date Helpers

The multiple selects that the date and time helpers (date_select, time_select, datetime_select) generate are wrapped inside a div.rails-bootstrap-forms-[date|time|datetime]-select tag. This is because Bootstrap automatically styles our controls as blocks. This wrapper fixes this defining these selects as inline-block and a width of auto.

Submit Buttons

The btn btn-secondary CSS classes are automatically added to your submit buttons.

<%= f.submit %>

You can also use the primary helper, which adds btn btn-primary to your submit button:

<%= f.primary "Optional Label" %>

You can specify your own classes like this:

<%= f.submit "Log In", class: "btn btn-success" %>

If the primary helper receives a render_as_button: true option or a block, it will be rendered as an HTML button, instead of an input tag. This allows you to specify HTML content and styling for your buttons (such as adding illustrative icons to them). For example, the following statements

<%= f.primary "Save changes <span class='fa fa-save'></span>".html_safe, render_as_button: true %>

<%= f.primary do
      concat 'Save changes '
      concat content_tag(:span, nil, class: 'fa fa-save')
    end %>

are equivalent, and each of them both be rendered as

<button name="button" type="submit" class="btn btn-primary">Save changes <span class="fa fa-save"></span></button>

If you wish to add additional CSS classes to your button, while keeping the default ones, you can use the extra_class option. This is particularly useful for adding extra details to buttons (without forcing you to repeat the Bootstrap classes), or for element targeting via CSS classes. Be aware, however, that using the class option will discard any extra classes you add. As an example, the following button declarations

<%= f.primary "My Nice Button", extra_class: 'my-button' %>

<%= f.primary "My Button", class: 'my-button' %>

will be rendered as

<input type="submit" value="My Nice Button" class="btn btn-primary my-button" />

<input type="submit" value="My Button" class="my-button" />

(some unimportant HTML attributes have been removed for simplicity)

Rich Text Areas AKA Trix Editor

If you're using Rails 6, and bootstrap_form from the master branch on GitHub, bootstrap_form supports the rich_text_area helper.

<%= f.rich_text_area(:life_story) %>

will be rendered as:

<div class="form-group">
  <label for="user_life_story">Life story</label>
  <input type="hidden" name="user[life_story]" id="user_life_story_trix_input_user"/>
  <trix-editor id="user_life_story" data-blob-url-template="http://test.host/rails/active_storage/blobs/:signed_id/:filename" data-direct-upload-url="http://test.host/rails/active_storage/direct_uploads" input="user_life_story_trix_input_user" class="trix-content form-control"/>
  </trix-editor>
</div>

To use bootstrap_form from the master branch of GitHub, change the bootstrap_form line in your Gemfile to:

gem "bootstrap_form", git: "https://github.com/bootstrap-ruby/bootstrap_form"

Support for rich_text_area is highly experimental at this time. Please submit bugs to the issue tracker.

Accessing Rails Form Helpers

If you want to use the original Rails form helpers for a particular field, append _without_bootstrap to the helper:

<%= f.text_field_without_bootstrap :email %>

Form Styles

By default, your forms will stack labels on top of controls and your controls will grow to 100% of the available width.

Inline Forms

To use an inline-layout form, use the layout: :inline option. To hide labels, use the hide_label: true option, which keeps your labels accessible to those using screen readers.

<%= bootstrap_form_for(@user, layout: :inline) do |f| %>
  <%= f.email_field :email, hide_label: true %>
  <%= f.password_field :password, hide_label: true %>
  <%= f.check_box :remember_me %>
  <%= f.submit %>
<% end %>

To skip label rendering at all, use skip_label: true option.

<%= f.password_field :password, skip_label: true %>

Horizontal Forms

To use a horizontal-layout form with labels to the left of the control, use the layout: :horizontal option. You should specify both label_col and control_col css classes as well (they default to col-sm-2 and col-sm-10).

In the example below, the checkbox and submit button have been wrapped in a form_group to keep them properly aligned.

<%= bootstrap_form_for(@user, layout: :horizontal, label_col: "col-sm-2", control_col: "col-sm-10") do |f| %>
  <%= f.email_field :email %>
  <%= f.password_field :password %>
  <%= f.form_group do %>
    <%= f.check_box :remember_me %>
  <% end %>
  <%= f.form_group do %>
    <%= f.submit %>
  <% end %>
<% end %>

The label_col and control_col css classes can also be changed per control:

<%= bootstrap_form_for(@user, layout: :horizontal) do |f| %>
  <%= f.email_field :email %>
  <%= f.text_field :age, control_col: "col-sm-3" %>
  <%= f.form_group do %>
    <%= f.submit %>
  <% end %>
<% end %>

or default value can be changed in initializer:

# config/initializers/bootstrap_form.rb
module BootstrapForm
  class FormBuilder
    def default_label_col
      'col-sm-4'
    end
    def default_control_col
      'col-sm-8'
    end
  end
end

Control col wrapper class can be modified with add_control_col_class. This option will preserve column definition:

<%= bootstrap_form_for(@user, layout: :horizontal) do |f| %>
  <%= f.email_field :email %>
  <%= f.text_field :age, add_control_col_class: "additional-control-col-class" %>
  <%= f.form_group do %>
    <%= f.submit %>
  <% end %>
<% end %>

Custom Field Layout

The form-level layout can be overridden per field, unless the form-level layout was inline:

<%= bootstrap_form_for(@user, layout: :horizontal) do |f| %>
  <%= f.email_field :email %>
  <%= f.text_field :feet, layout: :default %>
  <%= f.text_field :inches, layout: :default %>
  <%= f.form_group do %>
    <%= f.submit %>
  <% end %>
<% end %>

A form-level layout: :inline can't be overridden because of the way Bootstrap 4 implements in-line layouts. One possible work-around is to leave the form-level layout as default, and specify the individual fields as layout: :inline, except for the fields(s) that should be other than in-line.

Custom Form Element Styles

The custom option can be used to replace the browser default styles for check boxes and radio buttons with dedicated Bootstrap styled form elements. Here's an example:

<%= bootstrap_form_for(@user) do |f| %>
  <%= f.email_field :email %>
  <%= f.password_field :password %>
  <%= f.check_box :remember_me, custom: true %>
  <%= f.submit "Log In" %>
<% end %>

Validation and Errors

Inline Errors

By default, fields that have validation errors will be outlined in red and the error will be displayed below the field. Rails normally wraps the fields in a div (field_with_errors), but this behavior is suppressed. Here's an example:

<div class="form-group">
  <label class="form-control-label" for="user_email">Email</label>
  <input class="form-control is-invalid" id="user_email" name="user[email]" type="email" value="">
  <small class="invalid-feedback">can't be blank</small>
</div>

You can turn off inline errors for the entire form like this:

<%= bootstrap_form_for(@user, inline_errors: false) do |f| %>
  ...
<% end %>

Label Errors

You can also display validation errors in the field's label; just turn on the :label_errors option. Here's an example:

<%= bootstrap_form_for(@user, label_errors: true) do |f| %>
  ...
<% end %>

By default, turning on :label_errors will also turn off :inline_errors. If you want both turned on, you can do that too:

<%= bootstrap_form_for(@user, label_errors: true, inline_errors: true) do |f| %>
  ...
<% end %>

Alert Messages

To display an error message with an error summary, you can use the alert_message helper. This won't output anything unless a model validation has failed.

<%= f.alert_message "Please fix the errors below." %>

Which outputs:

<div class="alert alert-danger">
  <p>Please fix the errors below.</p>
  <ul class="rails-bootstrap-forms-error-summary">
    <li>Email can't be blank</li>
  </ul>
</div>

You can turn off the error summary like this:

<%= f.alert_message "Please fix the errors below.", error_summary: false %>

To output a simple unordered list of errors, use the error_summary helper.

<%= f.error_summary %>

Which outputs:

<ul class="rails-bootstrap-forms-error-summary">
  <li>Email can't be blank</li>
</ul>

Errors On

If you want to display a custom inline error for a specific attribute not represented by a form field, use the errors_on helper.

<%= f.errors_on :tasks %>

Which outputs:

<div class="alert alert-danger">Tasks can't be blank.</div>

You can hide the attribute name like this:

<%= f.errors_on :tasks, hide_attribute_name: true %>

Which outputs:

<div class="alert alert-danger">can't be blank.</div>

Internationalization

bootstrap_form follows standard rails conventions so it's i18n-ready. See more here: http://guides.rubyonrails.org/i18n.html#translations-for-active-record-models

Other Tips and Edge Cases

By their very nature, forms are extremely diverse. It would be extremely difficult to provide a gem that could handle every need. Here are some tips for handling edge cases.

Empty But Visible Labels

Some third party plug-ins require an empty but visible label on an input control. The hide_label option generates a label that won't appear on the screen, but it's considered invisible and therefore doesn't work with such a plug-in. An empty label (e.g. "") causes the underlying Rails helper to generate a label based on the field's attribute's name.

The solution is to use a zero-width character for the label, or some other "empty" HTML. For example:

label: "&#8203;".html_safe

or

label: "<span></span>".html_safe

Code Triage page

http://www.codetriage.com/potenza/bootstrap_form

Contributing

We welcome contributions. If you're considering contributing to bootstrap_form, please review the Contributing document first.

Files

OLD-README.md

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History

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File metadata and controls

bootstrap_form

Requirements

Installation

Usage

bootstrap_form_tag

bootstrap_form_with (Rails 5.1+)

Future Compatibility

Form Helpers

Labels

Required Fields

Input Elements / Controls

Help Text

Prepending and Appending Inputs

Additional Form Group Attributes

Suppressing the Form Group Altogether

Selects

Checkboxes and Radios

Switches

Collections

Static Controls

Date Helpers

Submit Buttons

Rich Text Areas AKA Trix Editor

Accessing Rails Form Helpers

Form Styles

Inline Forms

Horizontal Forms

Custom Field Layout

Custom Form Element Styles

Validation and Errors

Inline Errors

Label Errors

Alert Messages

Errors On

Internationalization

Other Tips and Edge Cases

Empty But Visible Labels

Code Triage page

Contributing

License

`bootstrap_form_with` (Rails 5.1+)