/ Ruby on Rails
/
method

field_id

rails latest stable - Class: ActionView::Helpers::FormBuilder
field_id(method, *suffixes, namespace: @options[:namespace], index: @options[:index])
public

Generate an HTML id attribute value for the given field

Return the value generated by the FormBuilder for the given attribute name.

<%= form_for @post do |f| %>
  <%= f.label :title %>
  <%= f.text_field :title, aria: { describedby: f.field_id(:title, :error) } %>
  <%= tag.span("is blank", id: f.field_id(:title, :error) %>
<% end %>

In the example above, the <input type="text"> element built by the call to FormBuilder#text_field declares an aria-describedby attribute referencing the <span> element, sharing a common id root (post_title, in this case).