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A basic form builder for outputting Bootstrap-specific markup
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A gem for building horizontal (vertial/search/inline coming soon) Twitter Bootstrap forms, automagically handling the control-group markup, field labels and inline-error messages.


Add this line to your application's Gemfile:

gem 'twitter-bootstrap-form-builder'

And then execute:

$ bundle

Or install it yourself as:

$ gem install twitter-bootstrap-form-builder



module ApplicationHelper
  # Replace form_for
  include MNE::TwitterBootstrapFormBuilder::Helper

Using the form builder

<% # Labels and control-group markup are handled by the form builder %>

<%= form_for @post do |f| %>
  <%= f.text_field :topic %>
  <%= f.text_area :body %>
  <div class="form-actions">
    <%= f.submit "Create Post" %>
<% end %>


Twitter Bootstrap FormBuilder is designed to output all the markup required to build horizontal forms, with minimal typing.

After installing the Gem, you can use the special form_for helper by mixing TwitterBootstrapFormBuilder::Helper into your Helper modules, which will automatically add the form-horizontal class to your <form> tag, and set the :builder to TwitterBootstrapFormBuilder. That is, the following are roughly equivalent:

# Using the TBFB helper:
form_for @post do |f|

# Using the regular form_for helper
form_for @post, :builder => MNE::TwitterBootstrapFormBuilder::FormBuilder, :html => { :class => "form-horizontal" } do |f|

Using the FormBuilder:

The various *_field and select methods will output the full markup for a control group, including labels.

The following text_field...

<%= form_for @post do |f| %>
  <%= f.text_field :subject %>

Outputs the following HTML:

<div class="text_field control-group subject">
  <label for="post_subject">Subject</label>
  <div class="controls">
     <input type="text" name="post[subject]" id="post_subject" value="..." />

If you need to override the text of the label, use :label:

<%= f.text_field :email, :label => "Email Address" %>

If you want to turn off the helper entirely for one field and output just the input/select/textarea element, exactly as if you were calling the regular FormBuilder#text_field, use :label => false:

<%= f.text_field :email, :label => false %> # <input type="text" id="post_email" />

To disable the Bootstrap FormBuilder for an entire form, use :bootstrap => false with form_for:

<%= form_for @post, :bootstrap => false do |f| %>

To render the field within the Bootstrap control-group markup but without a label tag, use :label => nil:

<%= f.text_field :email, :label => nil %>

Checkboxes are a special case. They can contain two labels in a horizontal form, on to the left and one to the right.

The left label uses the :label option and works as expected.

The right label is controled by the :text option.


<%= f.check_box :hide_email, :text=> "Do not display my email in my post" %>

Produces the following HTML:

<div class="control-group hide_email">
	<label class="control-label" for="post_hide_email">Hide email</label>
	<div class="controls">
		<label class="checkbox" for="post_hide_email">
			<input name="post[hide_email]" type="hidden" value="0" />
			<input id="post_hide_email" name="post[hide_email]" type="checkbox" value="1" />
			Do not display my email in my post

Errors and validation

The TwitterBootstrapFormBuilder relies on the dynamic_form gem to output inline error messages.

Outputting a field with errors will add an inline error message and decorate the top-level control-group with an error class, causing the field inside to be outlined in Red by bootstrap.css

Given a post with a "can't be blank" error on the topic field:

<%= form_for @post do |f| %>
  <%= f.text_field :topic %>
<% end %>

The following will be produced (a mixture of Rail's field_with_errors and Bootstrap-specific classes):

<div class="text_field control-group topic error">
  <div class="field_with_errors">
    <label for="post_topic">Topic</label>
  <div class="controls">
    <div class="field_with_errors">
      <input type="text" name="post[topic]" value="..." />
    <p class="help-block">Topic can't be blank</p>

Note that both the label and input elements are still wrapped in <div class="field_with_errors"> by the base FormBuilder. In addition, a <p class="help-block"> is output below the field containing the error message.

Rendering just some fields:

<%= fields_for @post, :builder => MNE::TwitterBootstrapFormBuilder::FormBuilder do |f| %>

Other helpers

If you want to output your own control group, you can use the control_group method to help with the markup.

<%= f.control_group :topic %> <!-- div class="control-group topic [error]" -->
  <%= f.label :topic %>
  <div class="controls">
    <%= f.text_field :topic, :label => false %>
    <div class="errors">
      <%= f.errors_for :topic %><!-- as provided by dynamic_form -->
<% end %>


Here is a basic form for a PhotoSet, which contains a title and description attribute. The form has been posted back, causing a validates_presence_of validator to fail on the title field:


<%= form_for [:admin, @photo_set] do |f| %>
  <%= f.text_field :title %>
  <%= f.text_area :description %>

  <div class="form-actions">
    <%= f.submit "Create Photo Set" %>
<% end %>

Output (cleaned up and indented):

<form accept-charset="UTF-8" action="/admin/photo_sets" class="form-horizontal" id="new_photo_set" method="post">
	<div style="margin:0;padding:0;display:inline">
		<input name="utf8" type="hidden" value="&#x2713;" />
		<input name="authenticity_token" type="hidden" value="nVRM9bXgeD2s/WGum+fJMy9dMYSNVCzYR6/U0Pg+068=" />
	<div class="text_field control-group title error">
		<div class="field_with_errors">
			<label class="control-label" for="photo_set_title">Title</label>
		<div class="controls">
			<div class="field_with_errors">
				<input id="photo_set_title" name="photo_set[title]" size="30" type="text" value="" />
			<p class="help-block">Title can't be blank</p>
	<div class="text_area control-group description">
		<label class="control-label" for="photo_set_description">Description</label>
		<div class="controls">
			<textarea cols="40" id="photo_set_description" name="photo_set[description]" rows="20">

	<div class="form-actions">
		<input name="commit" type="submit" value="Create Photo Set" />


  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Added some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request
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