Use Rails’ form_for but set custom classes, attributes on
element?

Question

form_for seems to ignore any 'extra' attributes like a data-foo attribute or class passed as options in its second argument.

= form_for @user, {:url => 'foo', :class => 'x', 'data-bar' => 'baz' } do |f|
  # ...

The output is a <form> tag with no x class or data-bar attribute.

What’s the fix?

Or, how can I grab a FormBuilder instance without using form_for?

score 225 · Accepted Answer · edited Dec 12 '19 at 08:59

225

Use the :html hash:

= form_for @user, :html => {:class => 'x', 'data-bar' => 'baz'} do |f|

Or

= form_for @user, html: {class: 'x', data: { bar: 'baz' } } do |f|

edited Dec 12 '19 at 08:59

Alan H.

answered Oct 30 '12 at 17:44

MurifoX

1

I found that this doesn't work: `= form_for @user, :html => {'class' => 'x'} do |f|`. `class` should be a symbol instead of string. – Trantor Liu Dec 17 '15 at 04:54

score 11 · Answer 2 · answered Aug 12 '14 at 21:32

11

Rails 4.0.3, Ruby 2.1.0p0 -> this worked for me =>

<%= form_for(@contact, :html => {:class => 'form_height'}) do |f| %><% if     @contact.errors.any? %>

answered Aug 12 '14 at 21:32

zero_cool

score 5 · Answer 3 · answered Jun 28 '16 at 07:50

I had the same problem but was puzzled that another form elsewhere in my app was working fine.

I realized that I had accidentally added a form_for inside another form_for which once removed cured the problem.

Secondly, I should add that this syntax works for me in Rails 4.2:

<%= form_for @type, html: {class: "form-horizontal"} do |f| %>

I find it preferable to the punctuation-soup of the other answers here (which were perhaps based on an older Rails version).

felipeclopes · Answer 4 · 2012-10-30T21:15:09.713

1

On mostly helpers, the last arg is a hash of html options for the element.

= form_for @user, :html => {:class => 'x', 'data-bar' => 'baz'} %>

You can also check other alternatives in the documentation ActionsView::Helpers::FormHelper

edited Oct 30 '12 at 21:15

answered Oct 30 '12 at 17:51

felipeclopes

score 1 · Answer 5 · answered Oct 28 '14 at 22:40

1

I tried the above with no luck but found a solution. I'm using rails 4.1.6.

This didn't work

= form_for @user, :html => {:class => 'x', 'data-bar' => 'baz'} %>

This did

= form_for @user, html: {:class => 'x', 'data-bar' => 'baz'} %>

notice the difference with the html option, hope this helps

answered Oct 28 '14 at 22:40

doz87

3

Wow, really? those should be exactly equivalent. You can reproduce this? Which version of Ruby are you using? – Alan H. Oct 29 '14 at 04:01
@Alan H. Using Ruby 2.1.3p242 `= form_for(:user, :url => login_path, html: {:class => 'login_form'}) do |f| %>` This was the only way that my code would apply the class, otherwise it was just ignoring it. – doz87 Oct 30 '14 at 00:07
Those two lines are exactly identical. Guessing you forgot to save in between? – nathanvda Jan 29 '15 at 14:05
I know, they should be. For me it just wasn't working though. Saving wasn't the issue. – doz87 Jan 30 '15 at 03:50

5 Answers5