Module ActionView::Helpers::FormHelper
In: vendor/rails/actionpack/lib/action_view/helpers/form_helper.rb

Provides a set of methods for working with forms and especially forms related to objects assigned to the template. The following is an example of a complete form for a person object that works for both creates and updates built with all the form helpers. The @person object was assigned by an action on the controller:

  <form action="save_person" method="post">
    Name:
    <%= text_field "person", "name", "size" => 20 %>

    Password:
    <%= password_field "person", "password", "maxsize" => 20 %>

    Single?:
    <%= check_box "person", "single" %>

    Description:
    <%= text_area "person", "description", "cols" => 20 %>

    <input type="submit" value="Save">
  </form>

…is compiled to:

  <form action="save_person" method="post">
    Name:
    <input type="text" id="person_name" name="person[name]"
      size="20" value="<%= @person.name %>" />

    Password:
    <input type="password" id="person_password" name="person[password]"
      size="20" maxsize="20" value="<%= @person.password %>" />

    Single?:
    <input type="checkbox" id="person_single" name="person[single] value="1" />

    Description:
    <textarea cols="20" rows="40" id="person_description" name="person[description]">
      <%= @person.description %>
    </textarea>

    <input type="submit" value="Save">
  </form>

If the object name contains square brackets the id for the object will be inserted. Example:

  <%= textfield "person[]", "name" %>

…becomes:

  <input type="text" id="person_<%= @person.id %>_name" name="person[<%= @person.id %>][name]" value="<%= @person.name %>" />

If the helper is being used to generate a repetitive sequence of similar form elements, for example in a partial used by render_collection_of_partials, the "index" option may come in handy. Example:

  <%= text_field "person", "name", "index" => 1 %>

becomes

  <input type="text" id="person_1_name" name="person[1][name]" value="<%= @person.name %>" />

There’s also methods for helping to build form tags in classes/ActionView/Helpers/FormOptionsHelper.html, classes/ActionView/Helpers/DateHelper.html, and classes/ActionView/Helpers/ActiveRecordHelper.html

Methods

Public Instance methods

Returns a checkbox tag tailored for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object). It’s intended that method returns an integer and if that integer is above zero, then the checkbox is checked. Additional options on the input tag can be passed as a hash with options. The checked_value defaults to 1 while the default unchecked_value is set to 0 which is convenient for boolean values. Usually unchecked checkboxes don’t post anything. We work around this problem by adding a hidden value with the same name as the checkbox.

Example (call, result). Imagine that @post.validated? returns 1:

  check_box("post", "validated")
    <input type="checkbox" id="post_validate" name="post[validated] value="1" checked="checked" />
    <input name="post[validated]" type="hidden" value="0" />

Example (call, result). Imagine that @puppy.gooddog returns no:

  check_box("puppy", "gooddog", {}, "yes", "no")
    <input type="checkbox" id="puppy_gooddog" name="puppy[gooddog] value="yes" />
    <input name="puppy[gooddog]" type="hidden" value="no" />

[Source]

     # File vendor/rails/actionpack/lib/action_view/helpers/form_helper.rb, line 123
123:       def check_box(object, method, options = {}, checked_value = "1", unchecked_value = "0")
124:         InstanceTag.new(object, method, self).to_check_box_tag(options, checked_value, unchecked_value)
125:       end

Works just like text_field, but returns a input tag of the "file" type instead, which won’t have any default value.

[Source]

    # File vendor/rails/actionpack/lib/action_view/helpers/form_helper.rb, line 90
90:       def file_field(object, method, options = {})
91:         InstanceTag.new(object, method, self).to_input_field_tag("file", options)
92:       end

Works just like text_field, but returns a input tag of the "hidden" type instead.

[Source]

    # File vendor/rails/actionpack/lib/action_view/helpers/form_helper.rb, line 85
85:       def hidden_field(object, method, options = {})
86:         InstanceTag.new(object, method, self).to_input_field_tag("hidden", options)
87:       end

Works just like text_field, but returns a input tag of the "password" type instead.

[Source]

    # File vendor/rails/actionpack/lib/action_view/helpers/form_helper.rb, line 80
80:       def password_field(object, method, options = {})
81:         InstanceTag.new(object, method, self).to_input_field_tag("password", options)
82:       end

Returns a radio button tag for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object). If the current value of method is tag_value the radio button will be checked. Additional options on the input tag can be passed as a hash with options. Example (call, result). Imagine that @post.category returns "rails":

  radio_button("post", "category", "rails")
  radio_button("post", "category", "java")
    <input type="radio" id="post_category" name="post[category] value="rails" checked="checked" />
    <input type="radio" id="post_category" name="post[category] value="java" />

[Source]

     # File vendor/rails/actionpack/lib/action_view/helpers/form_helper.rb, line 137
137:       def radio_button(object, method, tag_value, options = {})
138:         InstanceTag.new(object, method, self).to_radio_button_tag(tag_value, options)
139:       end

Returns a textarea opening and closing tag set tailored for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object). Additional options on the input tag can be passed as a hash with options.

Example (call, result):

  text_area("post", "body", "cols" => 20, "rows" => 40)
    <textarea cols="20" rows="40" id="post_body" name="post[body]">
      #{@post.body}
    </textarea>

[Source]

     # File vendor/rails/actionpack/lib/action_view/helpers/form_helper.rb, line 103
103:       def text_area(object, method, options = {})
104:         InstanceTag.new(object, method, self).to_text_area_tag(options)
105:       end

Returns an input tag of the "text" type tailored for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object). Additional options on the input tag can be passed as a hash with options.

Examples (call, result):

  text_field("post", "title", "size" => 20)
    <input type="text" id="post_title" name="post[title]" size="20" value="#{@post.title}" />

[Source]

    # File vendor/rails/actionpack/lib/action_view/helpers/form_helper.rb, line 75
75:       def text_field(object, method, options = {})
76:         InstanceTag.new(object, method, self).to_input_field_tag("text", options)
77:       end

[Validate]