Question

I have a simple form that looks like this:

 <%= simple_form_for @study,:url => studies_path, :html => { :class => 'form-horizontal' } do |f| %>
    <%= f.input :category, :collection => @categories, :label => "Category", :selected => @categories.first %>
  <%= f.button :submit, t('add_form'),:class => 'btn-primary' %>

I want to add a new field in that form that will be merely visual sugar. It will be a helper to dynamically change the :category field.

How do I do that?

Answer 1

Use text_field_tag or whichever other _tag helper to generate a form element without attaching it to any specific attribute of the model:

<%= simple_form_for @study,:url => studies_path, :html => { :class => 'form-horizontal' } do |f| %>
  <%= f.input :category, :collection => @categories, :label => "Category", :selected => @categories.first %>
  <%= text_field_tag :blah %>
  <%= f.button :submit, t('add_form'),:class => 'btn-primary' %>
<% end %>