ActionView::Helpers::FormTagHelper

radio_button_tag

def radio_button_tag(name, value, checked = false, options = {})

Description

Creates an <input> with type="radio" that is not tied to a model.

Arguments

Changing a value updates the ERB and HTML.

name

:plan

"user[plan]"

Used as the name attribute of the <input> and as the first part of its id. In the id, [, spaces and similar characters become _, and ] is removed.

value

Used as the value attribute and also appended to the id. In the id, spaces and similar characters become _, as with name. Unlike radio_button in FormHelper, it is not downcased and punctuation is not removed (letters, digits, ., : and - are kept, and any other character, such as punctuation or Japanese characters, becomes _, except that ] is removed).

checked = false

true

Any value other than false and nil adds the checked attribute (even "0" adds it).

options= {}

:value = nil

"basic"

Sets the value attribute, overriding the value argument. The id is still built from the value argument. nil omits value.

Common options

Rails handles these options the same way in every helper. Options the HTML spec does not allow on the <input>, and ones this site considers rarely used, are not listed here.

Shared by form helpers

:name = generated

"q"

Replaces the generated name with the given value. nil omits name.

:id = generated

nil

Replaces the generated id with the given value. nil omits id.

Shared by all helpers

:disabled

truefalse

true adds disabled="disabled"; false omits it. The same goes for every HTML attribute in Rails' list (BOOLEAN_ATTRIBUTES), such as readonly, required and autofocus: any value other than false or nil adds it as attr="attr".

:class

{active: true, hidden: false}

A hash gives the keys whose values are not false or nil, joined with spaces. An array gives its elements joined with spaces, after removing nil, false and empty strings (including whitespace-only strings).

:data

{controller: "tags", tags_suggestions_value: ["ruby", "rails"]}

A hash adds data-* attributes, with _ in the keys converted to -. Array and hash values are converted to JSON strings.

:aria

{describedby: ["name_help", "name_error"], invalid: false}

Like :data, adds aria-* attributes. Array values are joined with spaces, leaving out nil and empty strings (nothing is added if none remain). For a hash value, the keys whose values are not false or nil are joined with spaces.

Any other options become HTML attributes of the <input>; those with a nil value are left out.

ERB

Changes from the previous output: Added Removed Changed

HTML

Preview

Interacting with the preview updates the form submission.

Form submission

Form data

name	value

Request body

Content-Type:

params