bootstrap_form is a Rails form builder that makes it super easy to integrate Bootstrap v5-style forms into your Rails application. It provides form helpers that augment the Rails form helpers. bootstrap_forms's form helpers generate the form field and its label and all the Bootstrap mark-up required for proper Bootstrap display. bootstrap_form also provides:
- Validation error messages below the field they correspond to, by default. You can also put the error messages after the label, or turn off
bootstrap_form's validation error handling and do it yourself. Note that this applies to Rails-generated validation messages. HTML 5 client-side validation and Rails validation out of the box don't really work well together. One discussion of the challenges and some solutions is here - Automatic mark-up for the
requiredattribute on required fields. - An easy way to consistently show help text on fields.
- Mark-up for Bootstrap horizontal forms (labels to the left of their fields, like a traditional desktop application), if that's what you want.
- Many options to modify or augment the generated mark-up.
- A way to escape to the Rails form helpers if you need to do something that
bootstrap_formcan't do.
Some other nice things that bootstrap_form does for you are:
- Reduces the amount of code in your
.erbfiles. - Gets you going faster with Bootstrap, because you don't need to learn all the rules of Bootstrap form mark-up to get started.
- Reduces errors, because you're doing less typing.
- Makes it easier to see the logic of the form, because it's not mixed in with the Bootstrap mark-up.
bootstrap_form works like the standard Rails form helpers, and this README assumes you know how they work. You start a form with one of bootstrap_form_with, bootstrap_form_for, or bootstrap_form_tag in a view file. You get a form builder that calls the bootstrap_form helpers instead of the standard Rails helpers. You use that form builder in the view file to render one or more form fields.
bootstrap_form supports at a minimum the currently supported versions of Ruby and Rails:
- Ruby 2.5+
- Rails 5.2+
- Bootstrap 5.0+
Install Bootstrap 5. There are many ways to do this, depending on the asset pipeline you're using in your Rails application. One way is to use the gem that works with Sprockets. To do so, in a brand new Rails 7.0 application created without the --webpacker option, add the bootstrap gem to your Gemfile:
gem "bootstrap", "~> 5.0"And follow the remaining instructions in the official bootstrap installation guide for setting up application.scss and application.js.
Add the bootstrap_form gem to your Gemfile:
gem "bootstrap_form", "~> 5.1"Then:
bundle install
Depending on which CSS pre-processor you are using, adding the bootstrap form styles differs slightly.
If you use Rails in the default mode without any pre-processor, you'll have to add the following line to your application.css file:
*= require rails_bootstrap_formsIf you followed the official bootstrap installation guide, you'll probably have switched to SCSS. In this case add the following line to your application.scss:
@import "rails_bootstrap_forms";To get started, use the bootstrap_form_for helper in place of the Rails 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="mb-3">
<label class="form-label required" for="user_email">Email</label>
<input class="form-control" id="user_email" name="user[email]" type="email" value="steve@example.com">
</div>
<div class="mb-3">
<label class="form-label" for="user_password">Password</label>
<input class="form-control" id="user_password" name="user[password]" type="password">
</div>
<div class="form-check mb-3">
<input autocomplete="off" 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" data-disable-with="Log In" name="commit" type="submit" value="Log In">
</form>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 %>This generates:
<form accept-charset="UTF-8" action="/subscribe" method="post">
<div class="mb-3">
<label class="form-label" for="email">Email</label>
<input class="form-control" id="email" name="email" type="email" value="name@example.com">
</div>
<input class="btn btn-secondary" data-disable-with="Save " name="commit" type="submit" value="Save ">
</form>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 behaviour 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, help: 'A good password should be at least six characters long' %>
<%= f.check_box :remember_me %>
<%= f.submit "Log In" %>
<% end %>This generates:
<form accept-charset="UTF-8" action="/users" method="post">
<div class="mb-3">
<label class="form-label required" for="user_email">Email</label>
<input class="form-control" id="user_email" name="user[email]" type="email" value="steve@example.com">
</div>
<div class="mb-3">
<label class="form-label" for="user_password">Password</label>
<input class="form-control" id="user_password" name="user[password]" type="password">
<small class="form-text text-muted">A good password should be at least six characters long</small>
</div>
<div class="form-check mb-3">
<input autocomplete="off" 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" data-disable-with="Log In" name="commit" type="submit" value="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.
bootstrap_form can be used out-of-the-box without any configuration. However, bootstrap_form does have an optional configuration file at config/initializers/bootstrap_form.rb for setting options that affect all generated forms in an application.
The current configuration options are:
| Option | Default value | Description |
|---|---|---|
default_form_attributes |
bootstrap_form versions 3 and 4 added a role="form" attribute to all forms. The W3C validator will raise a warning on forms with a role="form" attribute. bootstrap_form version 5 drops this attribute by default. Set this option to { role: "form" } to make forms non-compliant with W3C, but generate the role="form" attribute like bootstrap_form versions 3 and 4. |
Example:
# config/initializers/bootstrap_form.rb
BootstrapForm.configure do |c|
c.default_form_attributes = { role: "form" } # to make forms non-compliant with W3C.
endbootstrap_form provides its own version of the following Rails form helpers:
button email_field search_field
check_box file_field select
collection_check_boxes grouped_collection_select submit
collection_radio_buttons hidden_field (not wrapped, but supported) telephone_field
collection_select month_field text_area
color_field number_field text_field
date_field password_field time_field
date_select phone_field time_select
datetime_field radio_button time_zone_select
datetime_local_field range_field url_field
datetime_select rich_text_area (Rails 6+) week_field
By default, the helpers generate a label tag, and an input, select, or textarea tag, by calling the Rails label helper, and then the Rails helper with the same name as the bootstrap_form helper.
The bootstrap_form helpers accept the same options as the standard Rails form helpers, and pass those options through to the Rails helper. They also accept additional options, described in the following section.
Many of the helpers accept the same options. The exceptions are:
button, check_box, collection_check_boxes, collection_radio_buttons, collection_select, date_select, datetime_select, file_field, grouped_collection_select, hidden_field, radio_button, rich_text_area, select, submit, time_select, time_zone_select
The options for the form helpers that aren't in the exceptions list are described in the following sub-sections:
Use the label option if you want to specify the field's label text:
<%= f.password_field :password_confirmation, label: "Confirm Password" %>This generates:
<div class="mb-3">
<label class="form-label" for="user_password_confirmation">Confirm Password</label>
<input class="form-control" id="user_password_confirmation" name="user[password_confirmation]" type="password">
</div>To hide a label, use the hide_label: true option. This adds the visually-hidden
class, which keeps your labels accessible to those using screen readers.
<%= f.text_area :comment, hide_label: true, placeholder: "Leave a comment..." %>This generates:
<div class="mb-3">
<label class="form-label visually-hidden" for="user_comment">Comment</label>
<textarea class="form-control" id="user_comment" name="user[comment]" placeholder="Leave a comment...">
</textarea>
</div>To add custom classes to the field's label:
<%= f.text_field :email, label_class: "custom-class" %>This generates:
<div class="mb-3">
<label class="form-label custom-class required" for="user_email">Email</label>
<input class="form-control" id="user_email" name="user[email]" type="text" value="steve@example.com">
</div>Or you can add the label as input placeholder instead (this automatically hides the label):
<%= f.text_field :email, label_as_placeholder: true %>This generates:
<div class="mb-3">
<label class="form-label visually-hidden required" for="user_email">Email</label>
<input class="form-control" id="user_email" name="user[email]" placeholder="Email" type="text" value="steve@example.com">
</div>To specify the class of the generated input tag, use the control_class option:
<%= f.text_field :email, control_class: "custom-class" %>This generates:
<div class="mb-3">
<label class="form-label required" for="user_email">Email</label>
<input class="custom-class" id="user_email" name="user[email]" type="text" value="steve@example.com">
</div>To add help text, use the help option:
<%= f.password_field :password, help: "Must be at least 6 characters long" %>This generates:
<div class="mb-3">
<label class="form-label" for="user_password">Password</label>
<input class="form-control" id="user_password" name="user[password]" type="password">
<small class="form-text text-muted">Must be at least 6 characters long</small>
</div>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.
You can pass prepend and/or append options to input fields:
<%= f.text_field :price, prepend: "$", append: ".00" %>This generates:
<div class="mb-3">
<label class="form-label" for="user_price">Price</label>
<div class="input-group">
<span class="input-group-text">$</span>
<input class="form-control" id="user_price" name="user[price]" type="text">
<span class="input-group-text">.00</span>
</div>
</div>If you want to attach multiple items to the input, pass them as an array:
<%= f.text_field :price, prepend: ['Net', '$'], append: ['.00', 'per day'] %>This generates:
<div class="mb-3">
<label class="form-label" for="user_price">Price</label>
<div class="input-group">
<span class="input-group-text">Net</span>
<span class="input-group-text">$</span>
<input class="form-control" id="user_price" name="user[price]" type="text">
<span class="input-group-text">.00</span>
<span class="input-group-text">per day</span>
</div>
</div>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") %>This generates:
<div class="mb-3">
<label class="form-label" for="user_search">Search</label>
<div class="input-group">
<input class="form-control" id="user_search" name="user[search]" type="text">
<a class="btn btn-secondary" href="#">Go</a>
</div>
</div>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' %>This generates:
<div class="mb-3">
<label class="form-label required" for="user_email">Email</label>
<div class="input-group input-group-lg">
<input class="form-control" id="user_email" name="user[email]" type="email" value="steve@example.com">
<input class="btn btn-primary" data-disable-with="Subscribe" name="commit" type="submit" value="Subscribe">
</div>
</div>Bootstrap mark-up dictates that most input field types have the label and input wrapped in a div.mb-3.
If you want to change the CSS class or any other attribute to the form group div, you can use the wrapper: { class: 'mb-3 additional-class', data: { foo: 'bar' } } option.
<%= f.text_field :name, wrapper: { class: 'mb-3 has-warning', data: { foo: 'bar' } } %>This generates:
<div class="mb-3 has-warning" data-foo="bar">
<label class="form-label" for="user_name">Name</label>
<input class="form-control" id="user_name" name="user[name]" type="text">
</div>Which produces the following output:
<div class="mb-3 has-warning" data-foo="bar">
<label class="form-label form-control-label" for="user_name">Id</label>
<input class="form-control" id="user_name" name="user[name]" type="text">
</div>This generates:
<div class="mb-3 has-warning" data-foo="bar">
<label class="form-label form-control-label" for="user_name">Id</label>
<input class="form-control" id="user_name" name="user[name]" type="text">
</div>If you only want to set the class on the form group div, you can use the wrapper_class option: wrapper_class: 'mb-3 additional-class'.
It's just a short form of wrapper: { class: 'mb-3 additional-class' }.
If you don't want any class on the form group div, you can set it to false: wrapper_class: false.
You may 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 %>Generated HTML:
<div class="mb-3">
<input class="form-control" id="user_email" name="user[email]" type="email" value="steve@example.com">
</div>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.
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" } %>This generates:
<div class="has-warning" data-foo="bar">
<label class="form-label" for="user_product">Choose your favorite fruit:</label>
<select class="form-select selectpicker" id="user_product" name="user[product]">
<option value="1">Apple</option>
<option value="2">Grape</option>
</select>
</div>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 %>This generates:
<div class="mb-3">
<label class="form-label" for="user_skill_level">Skill</label>
<div class="form-check">
<input checked class="form-check-input" id="user_skill_level_0" name="user[skill_level]" type="radio" value="0">
<label class="form-check-label" for="user_skill_level_0">Novice</label>
</div>
<div class="form-check">
<input class="form-check-input" id="user_skill_level_1" name="user[skill_level]" type="radio" value="1">
<label class="form-check-label" for="user_skill_level_1">Intermediate</label>
</div>
<div class="form-check">
<input class="form-check-input" id="user_skill_level_2" name="user[skill_level]" type="radio" value="2">
<label class="form-check-label" for="user_skill_level_2">Advanced</label>
</div>
<small class="form-text text-muted">Optional Help Text</small>
</div>
<div class="mb-3">
<div class="form-check mb-3">
<input autocomplete="off" name="user[terms]" type="hidden" value="0">
<input class="form-check-input" id="user_terms" name="user[terms]" type="checkbox" value="1">
<label class="form-check-label" for="user_terms">I agree to the Terms of Service</label>
</div>
</div>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 %>This generates:
<div class="mb-3">
<label class="form-label" for="user_terms">Optional Label</label>
<div class="form-check mb-3">
<input autocomplete="off" name="user[terms]" type="hidden" value="0">
<input class="form-check-input" id="user_terms" name="user[terms]" type="checkbox" value="1">
<label class="form-check-label" for="user_terms">
You need to check this box to accept our terms of service and privacy policy
</label>
</div>
</div>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 %>This generates:
<div class="mb-3">
<label class="form-label" for="user_skill_level">Skill</label>
<div class="form-check form-check-inline">
<input class="form-check-input" id="user_skill_level_0" name="user[skill_level]" type="radio" value="0">
<label class="form-check-label" for="user_skill_level_0">Novice</label>
</div>
<div class="form-check form-check-inline">
<input class="form-check-input" id="user_skill_level_1" name="user[skill_level]" type="radio" value="1">
<label class="form-check-label" for="user_skill_level_1">Intermediate</label>
</div>
<div class="form-check form-check-inline">
<input class="form-check-input" id="user_skill_level_2" name="user[skill_level]" type="radio" value="2">
<label class="form-check-label" for="user_skill_level_2">Advanced</label>
</div>
</div>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" %>This generates:
<div class="form-check form-check-inline w-auto">
<input class="form-check-input" id="user_skill_level_0" name="user[skill_level]" type="radio" value="0">
<label class="form-check-label" for="user_skill_level_0">Novice</label>
</div>You can also add a style to the tag using the wrapper option:
<%= f.check_box :skilled, inline: true, wrapper: {style: "color: green"} %>
<%= f.radio_button :skill_level, 0, label: "Novice", inline: true, wrapper: {class: 'w-auto', style: "color: red"} %>This generates:
<div class="form-check form-check-inline mb-3" style="color: green">
<input autocomplete="off" name="user[skilled]" type="hidden" value="0">
<input class="form-check-input" id="user_skilled" name="user[skilled]" type="checkbox" value="1">
<label class="form-check-label" for="user_skilled">Skilled</label>
</div>
<div class="form-check form-check-inline w-auto" style="color: red">
<input class="form-check-input" id="user_skill_level_0" name="user[skill_level]" type="radio" value="0">
<label class="form-check-label" for="user_skill_level_0">Novice</label>
</div>To render checkboxes as switches with Bootstrap 4.2+, use switch: true:
<%= f.check_box :remember_me, switch: true %>This generates:
<div class="form-check mb-3 form-switch">
<input autocomplete="off" 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>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 %>This generates:
<div class="mb-3">
<label class="form-label" for="user_skill_level">Skill level</label>
<div class="form-check">
<input class="form-check-input" id="user_skill_level_1" name="user[skill_level]" type="radio" value="1">
<label class="form-check-label" for="user_skill_level_1">Mind reading</label>
</div>
<div class="form-check">
<input class="form-check-input" id="user_skill_level_2" name="user[skill_level]" type="radio" value="2">
<label class="form-check-label" for="user_skill_level_2">Farming</label>
</div>
</div>
<input autocomplete="off" id="user_skills" multiple name="user[skills][]" type="hidden" value="">
<div class="mb-3">
<label class="form-label" for="user_skills">Skills</label>
<div class="form-check">
<input class="form-check-input" id="user_skills_1" name="user[skills][]" type="checkbox" value="1">
<label class="form-check-label" for="user_skills_1">Mind reading</label>
</div>
<div class="form-check">
<input class="form-check-input" id="user_skills_2" name="user[skills][]" type="checkbox" value="2">
<label class="form-check-label" for="user_skills_2">Farming</label>
</div>
</div>NOTE: These helpers do not currently support a block, unlike their equivalent Rails helpers. See issue #477. If you need to use the block syntax, use collection_check_boxes_without_bootstrap or collection_radio_buttons_without_bootstrap for now.
Collection methods accept these options:
:label: Customize theform_group's label:hide_label: Pass true to hide theform_group's label:help: Add a help span to theform_group- Other options will be forwarded to the
radio_button/check_boxmethod
You can create a range control like this:
<%= f.range_field :excellence %>This generates:
<div class="mb-3">
<label class="form-label" for="user_excellence">Excellence</label>
<input class="form-control" id="user_excellence" name="user[excellence]" type="range">
</div>You can create a static control like this:
<%= f.static_control :email %>This generates:
<div class="mb-3">
<label class="form-label required" for="user_email">Email</label>
<input class="form-control-plaintext" id="user_email" name="user[email]" readonly type="text" value="steve@example.com">
</div>Here's the output for a horizontal layout:
<%= bootstrap_form_for(@user, layout: :horizontal) do |f| %>
<%= f.static_control :email %>
<% end %>This generates:
<form accept-charset="UTF-8" action="/users" class="new_user" id="new_user" method="post">
<div class="mb-3 row">
<label class="form-label col-form-label col-sm-2 required" for="user_email">Email</label>
<div class="col-sm-10">
<input class="form-control-plaintext" id="user_email" name="user[email]" readonly type="text" value="steve@example.com">
</div>
</div>
</form>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" %>This generates:
<div class="mb-3">
<label class="form-label" for="user_field_name">Custom Static Control</label>
<input class="form-control-plaintext" id="user_field_name" name="user[field_name]" readonly type="text" value="Content Here">
</div>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 %>This generates:
<div class="mb-3">
<label class="form-label" for="user_">Custom Static Control</label>
<input class="form-control-plaintext" id="user_" readonly type="text" value="Content Here">
</div>(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.
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.
The btn btn-secondary CSS classes are automatically added to your submit
buttons.
<%= f.submit %>This generates:
<input class="btn btn-secondary" data-disable-with="Create User" name="commit" type="submit" value="Create User">You can also use the primary helper, which adds btn btn-primary to your
submit button:
<%= f.primary "Optional Label" %>This generates:
<input class="btn btn-primary" data-disable-with="Optional Label" name="commit" type="submit" value="Optional Label">You can specify your own classes like this:
<%= f.submit "Log In", class: "btn btn-success" %>This generates:
<input class="btn btn-success" data-disable-with="Log In" name="commit" type="submit" value="Log In">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 %>This generates:
<button class="btn btn-primary" name="button" type="submit">Save changes <span class="fa fa-save">
</span>
</button>
<button class="btn btn-primary" name="button" type="submit">Save changes <span class="fa fa-save">
</span>
</button>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 class="btn btn-primary my-button" data-disable-with="My Nice Button" name="commit" type="submit" value="My Nice Button">
<input class="my-button" data-disable-with="My Button" name="commit" type="submit" value="My Button">(some unimportant HTML attributes have been removed for simplicity)
If you're using Rails 6, bootstrap_form supports the rich_text_area helper.
<%= f.rich_text_area(:life_story) %>will be rendered as:
<div class="mb-3">
<label class="form-label" for="user_life_story">Life story</label>
<input autocomplete="off" id="user_life_story_trix_input_user" name="user[life_story]" type="hidden">
<trix-toolbar id="trix-toolbar-1">
<div class="trix-button-row">
<span class="trix-button-group trix-button-group--text-tools" data-trix-button-group="text-tools">
<button class="trix-button trix-button--icon trix-button--icon-bold" data-trix-attribute="bold" data-trix-key="b" tabindex="-1" title="Bold" type="button">Bold</button>
<button class="trix-button trix-button--icon trix-button--icon-italic" data-trix-attribute="italic" data-trix-key="i" tabindex="-1" title="Italic" type="button">Italic</button>
<button class="trix-button trix-button--icon trix-button--icon-strike" data-trix-attribute="strike" tabindex="-1" title="Strikethrough" type="button">Strikethrough</button>
<button class="trix-button trix-button--icon trix-button--icon-link" data-trix-action="link" data-trix-attribute="href" data-trix-key="k" tabindex="-1" title="Link" type="button">Link</button>
</span>
<span class="trix-button-group trix-button-group--block-tools" data-trix-button-group="block-tools">
<button class="trix-button trix-button--icon trix-button--icon-heading-1" data-trix-attribute="heading1" tabindex="-1" title="Heading" type="button">Heading</button>
<button class="trix-button trix-button--icon trix-button--icon-quote" data-trix-attribute="quote" tabindex="-1" title="Quote" type="button">Quote</button>
<button class="trix-button trix-button--icon trix-button--icon-code" data-trix-attribute="code" tabindex="-1" title="Code" type="button">Code</button>
<button class="trix-button trix-button--icon trix-button--icon-bullet-list" data-trix-attribute="bullet" tabindex="-1" title="Bullets" type="button">Bullets</button>
<button class="trix-button trix-button--icon trix-button--icon-number-list" data-trix-attribute="number" tabindex="-1" title="Numbers" type="button">Numbers</button>
<button class="trix-button trix-button--icon trix-button--icon-decrease-nesting-level" data-trix-action="decreaseNestingLevel" tabindex="-1" title="Decrease Level" type="button">Decrease Level</button>
<button class="trix-button trix-button--icon trix-button--icon-increase-nesting-level" data-trix-action="increaseNestingLevel" tabindex="-1" title="Increase Level" type="button">Increase Level</button>
</span>
<span class="trix-button-group trix-button-group--file-tools" data-trix-button-group="file-tools">
<button class="trix-button trix-button--icon trix-button--icon-attach" data-trix-action="attachFiles" tabindex="-1" title="Attach Files" type="button">Attach Files</button>
</span>
<span class="trix-button-group-spacer">
</span>
<span class="trix-button-group trix-button-group--history-tools" data-trix-button-group="history-tools">
<button class="trix-button trix-button--icon trix-button--icon-undo" data-trix-action="undo" data-trix-key="z" tabindex="-1" title="Undo" type="button">Undo</button>
<button class="trix-button trix-button--icon trix-button--icon-redo" data-trix-action="redo" data-trix-key="shift+z" tabindex="-1" title="Redo" type="button">Redo</button>
</span>
</div>
<div class="trix-dialogs" data-trix-dialogs="">
<div class="trix-dialog trix-dialog--link" data-trix-dialog="href" data-trix-dialog-attribute="href">
<div class="trix-dialog__link-fields">
<input aria-label="URL" class="trix-input trix-input--dialog" data-trix-input="" disabled name="href" placeholder="Enter a URL…" required="" type="url">
<div class="trix-button-group">
<input class="trix-button trix-button--dialog" data-trix-method="setAttribute" type="button" value="Link">
<input class="trix-button trix-button--dialog" data-trix-method="removeAttribute" type="button" value="Unlink">
</div>
</div>
</div>
</div>
</trix-toolbar>
<trix-editor aria-label="Life story" class="trix-content form-control" contenteditable="" data-blob-url-template="http://test.host/rails/active_storage/blobs/redirect/:signed_id/:filename" data-direct-upload-url="http://test.host/rails/active_storage/direct_uploads" id="user_life_story" input="user_life_story_trix_input_user" role="textbox" toolbar="trix-toolbar-1" trix-id="1">
</trix-editor>
</div>The file_field helper generates mark-up for a Bootstrap 4 custom file field entry. It takes the options for text_field, minus append and prepend.
Hidden Fields
The hidden_field helper in bootstrap_form calls the Rails helper directly, and does no additional mark-up.
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 %>This generates:
<input id="user_email" name="user[email]" type="text" value="steve@example.com">By default, your forms will stack labels on top of controls and your controls will grow to 100 percent of the available width. This is consistent with Bootstrap's "mobile first" approach.
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 %>This generates:
<form accept-charset="UTF-8" action="/users" class="new_user row row-cols-auto g-3 align-items-center" id="new_user" method="post">
<div class="col">
<label class="form-label visually-hidden mr-sm-2 required" for="user_email">Email</label>
<input class="form-control" id="user_email" name="user[email]" type="email" value="steve@example.com">
</div>
<div class="col">
<label class="form-label visually-hidden mr-sm-2" for="user_password">Password</label>
<input class="form-control" id="user_password" name="user[password]" type="password">
</div>
<div class="form-check form-check-inline mb-3">
<input autocomplete="off" 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>
<div class="col">
<input class="btn btn-secondary" data-disable-with="Create User" name="commit" type="submit" value="Create User">
</div>
</form>To skip label rendering at all, use skip_label: true option.
<%= f.password_field :password, skip_label: true %>This generates:
<div class="mb-3">
<input class="form-control" id="user_password" name="user[password]" type="password">
</div>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 %>This generates:
<form accept-charset="UTF-8" action="/users" class="new_user" id="new_user" method="post">
<div class="mb-3 row">
<label class="form-label col-form-label col-sm-2 required" for="user_email">Email</label>
<div class="col-sm-10">
<input class="form-control" id="user_email" name="user[email]" type="email" value="steve@example.com">
</div>
</div>
<div class="mb-3 row">
<label class="form-label col-form-label col-sm-2" for="user_password">Password</label>
<div class="col-sm-10">
<input class="form-control" id="user_password" name="user[password]" type="password">
</div>
</div>
<div class="mb-3 row">
<div class="col-sm-10 offset-sm-2">
<div class="form-check">
<input autocomplete="off" 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>
</div>
</div>
<div class="mb-3 row">
<div class="col-sm-10 offset-sm-2">
<input class="btn btn-secondary" data-disable-with="Create User" name="commit" type="submit" value="Create User">
</div>
</div>
</form>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 %>This generates:
<form accept-charset="UTF-8" action="/users" class="new_user" id="new_user" method="post">
<div class="mb-3 row">
<label class="form-label col-form-label col-sm-2 required" for="user_email">Email</label>
<div class="col-sm-10">
<input class="form-control" id="user_email" name="user[email]" type="email" value="steve@example.com">
</div>
</div>
<div class="mb-3 row">
<label class="form-label col-form-label col-sm-2" for="user_age">Age</label>
<div class="col-sm-3">
<input class="form-control" id="user_age" name="user[age]" type="text" value="42">
</div>
</div>
<div class="mb-3 row">
<div class="col-sm-10 offset-sm-2">
<input class="btn btn-secondary" data-disable-with="Create User" name="commit" type="submit" value="Create User">
</div>
</div>
</form>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
def default_layout
# :default, :horizontal or :inline
:horizontal
end
end
endControl 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 %>This generates:
<form accept-charset="UTF-8" action="/users" class="new_user" id="new_user" method="post">
<div class="mb-3 row">
<label class="form-label col-form-label col-sm-2 required" for="user_email">Email</label>
<div class="col-sm-10">
<input class="form-control" id="user_email" name="user[email]" type="email" value="steve@example.com">
</div>
</div>
<div class="mb-3 row">
<label class="form-label col-form-label col-sm-2" for="user_age">Age</label>
<div class="col-sm-10 additional-control-col-class">
<input class="form-control" id="user_age" name="user[age]" type="text" value="42">
</div>
</div>
<div class="mb-3 row">
<div class="col-sm-10 offset-sm-2">
<input class="btn btn-secondary" data-disable-with="Create User" name="commit" type="submit" value="Create User">
</div>
</div>
</form>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 %>This generates:
<form accept-charset="UTF-8" action="/users" class="new_user" id="new_user" method="post">
<div class="mb-3 row">
<label class="form-label col-form-label col-sm-2 required" for="user_email">Email</label>
<div class="col-sm-10">
<input class="form-control" id="user_email" name="user[email]" type="email" value="steve@example.com">
</div>
</div>
<div class="mb-3">
<label class="form-label" for="user_feet">Feet</label>
<input class="form-control" id="user_feet" name="user[feet]" type="text" value="5">
</div>
<div class="mb-3">
<label class="form-label" for="user_inches">Inches</label>
<input class="form-control" id="user_inches" name="user[inches]" type="text" value="7">
</div>
<div class="mb-3 row">
<div class="col-sm-10 offset-sm-2">
<input class="btn btn-secondary" data-disable-with="Create User" name="commit" type="submit" value="Create User">
</div>
</div>
</form>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.
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 %>This generates:
<form accept-charset="UTF-8" action="/users" class="new_user" id="new_user" method="post">
<div class="mb-3">
<label class="form-label required" for="user_email">Email</label>
<input class="form-control" id="user_email" name="user[email]" type="email" value="steve@example.com">
</div>
<div class="mb-3">
<label class="form-label" for="user_password">Password</label>
<input class="form-control" id="user_password" name="user[password]" type="password">
</div>
<div class="form-check mb-3">
<input autocomplete="off" name="user[remember_me]" type="hidden" value="0">
<input class="form-check-input" custom="true" 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" data-disable-with="Log In" name="commit" type="submit" value="Log In">
</form>The floating option can be used to enable Bootstrap 5's floating labels. This option is supported on text fields
and dropdowns. Here's an example:
<%= bootstrap_form_for(@user) do |f| %>
<%= f.email_field :email, floating: true %>
<%= f.password_field :password, floating: true %>
<%= f.password_field :password, floating: true %>
<%= f.select :status, [["Active", 1], ["Inactive", 2]], include_blank: "Select a value", floating: true %>
<%= f.submit "Log In" %>
<% end %>This generates:
<form accept-charset="UTF-8" action="/users" class="new_user" id="new_user" method="post">
<div class="mb-3 form-floating">
<input class="form-control" id="user_email" name="user[email]" placeholder="Email" type="email" value="steve@example.com">
<label class="form-label required" for="user_email">Email</label>
</div>
<div class="mb-3 form-floating">
<input class="form-control" id="user_password" name="user[password]" placeholder="Password" type="password">
<label class="form-label" for="user_password">Password</label>
</div>
<div class="mb-3 form-floating">
<input class="form-control" id="user_password" name="user[password]" placeholder="Password" type="password">
<label class="form-label" for="user_password">Password</label>
</div>
<div class="mb-3 form-floating">
<select class="form-select" id="user_status" name="user[status]">
<option value="">Select a value</option>
<option value="1">Active</option>
<option value="2">Inactive</option>
</select>
<label class="form-label" for="user_status">Status</label>
</div>
<input class="btn btn-secondary" data-disable-with="Log In" name="commit" type="submit" value="Log In">
</form>Rails normally wraps fields with validation errors in a div.field_with_errors, but this behaviour isn't consistent with Bootstrap 4 styling. By default, bootstrap_form generations in-line errors which appear below the field. But it can also generate errors on the label, or not display any errors, leaving it up to you.
By default, fields that have validation errors will be outlined in red and the error will be displayed below the field. Here's an example:
<div class="mb-3">
<label class="form-label 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 %>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 %>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.
<%= bootstrap_form_for @user_with_error do |f| %>
<%= f.alert_message "Please fix the errors below." %>
<% end %>Which outputs:
<form accept-charset="UTF-8" action="/users" class="new_user" id="new_user" method="post">
<div class="alert alert-danger">
<p>Please fix the errors below.</p>
<ul class="rails-bootstrap-forms-error-summary">
<li>Email is invalid</li>
<li>Misc is invalid</li>
</ul>
</div>
</form>You can turn off the error summary like this:
<%= bootstrap_form_for @user_with_error do |f| %>
<%= f.alert_message "Please fix the errors below.", error_summary: false %>
<% end %>This generates:
<form accept-charset="UTF-8" action="/users" class="new_user" id="new_user" method="post">
<div class="alert alert-danger">Please fix the errors below.</div>
</form>To output a simple unordered list of errors, use the error_summary helper.
<%= bootstrap_form_for @user_with_error do |f| %>
<%= f.error_summary %>
<% end %>Which outputs:
<form accept-charset="UTF-8" action="/users" class="new_user" id="new_user" method="post">
<ul class="rails-bootstrap-forms-error-summary">
<li>Email is invalid</li>
<li>Misc is invalid</li>
</ul>
</form>If you want to display a custom inline error for a specific attribute not represented by a form field, use the errors_on helper.
<%= bootstrap_form_for @user_with_error do |f| %>
<%= f.errors_on :email %>
<% end %>Which outputs:
<form accept-charset="UTF-8" action="/users" class="new_user" id="new_user" method="post">
<div class="invalid-feedback">Email is invalid</div>
</form>You can hide the attribute name like this:
<%= bootstrap_form_for @user_with_error do |f| %>
<%= f.errors_on :email, hide_attribute_name: true %>
<% end %>Which outputs:
<form accept-charset="UTF-8" action="/users" class="new_user" id="new_user" method="post">
<div class="invalid-feedback">is invalid</div>
</form>You can also use a custom class for the wrapping div, like this:
<%= bootstrap_form_for @user_with_error do |f| %>
<%= f.errors_on :email, custom_class: 'custom-error' %>
<% end %>Which outputs:
<form accept-charset="UTF-8" action="/users" class="new_user" id="new_user" method="post">
<div class="custom-error">Email is invalid</div>
</form>A label that is associated with a required field is automatically annotated with
a required CSS class. bootstrap_form doesn't provide any styling for required fields. You're 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 behaviour 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 %>This generates:
<div class="mb-3">
<label class="form-label required" for="user_login">New Username</label>
<input class="form-control" id="user_login" name="user[login]" required="required" type="password">
</div>
<div class="mb-3">
<label class="form-label" for="user_password">New Password</label>
<input class="form-control" id="user_password" name="user[password]" type="password">
</div>Adding a form control for a belongs_to field will automatically pick up the associated presence validator.
<%= bootstrap_form_for(@address, url: '/address') do |f| %>
<%= f.collection_select :user_id, @users, :id, :email, include_blank: "Select a value" %>
<%= f.text_field :street %>
<%= f.text_field :city %>
<%= f.text_field :state %>
<%= f.text_field :zip_code %>
<%= f.submit "Save" %>
<% end %>Generated HTML:
<form accept-charset="UTF-8" action="/address" class="new_address" id="new_address_1" method="post">
<div class="mb-3">
<label class="form-label required" for="address_user_id">User</label>
<select class="form-select" id="address_user_id" name="address[user_id]">
<option value="">Select a value</option>
<option value="">steve@example.com</option>
</select>
</div>
<div class="mb-3">
<label class="form-label" for="address_street">Street</label>
<input class="form-control" id="address_street" name="address[street]" type="text" value="Foo">
</div>
<div class="mb-3">
<label class="form-label" for="address_city">City</label>
<input class="form-control" id="address_city" name="address[city]" type="text">
</div>
<div class="mb-3">
<label class="form-label" for="address_state">State</label>
<input class="form-control" id="address_state" name="address[state]" type="text">
</div>
<div class="mb-3">
<label class="form-label" for="address_zip_code">Zip code</label>
<input class="form-control" id="address_zip_code" name="address[zip_code]" type="text">
</div>
<input class="btn btn-secondary" data-disable-with="Save" name="commit" type="submit" value="Save">
</form>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
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.
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.
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: "​".html_safeor
label: "<span></span>".html_safeWe welcome contributions. If you're considering contributing to bootstrap_form, please review the Contributing document first.
If you're looking for bootstrap_form for Bootstrap 4, go here.
MIT License. Copyright 2012-2021 Stephen Potenza (https://github.com/potenza) and others