<% @user = MarkupUser.new %> <% form_for @user , '/demo1', :id => 'demo-fields-for' do |f| %> <%= f.text_field :gender %> <% fields_for @user.permission do |permission| %> <%= permission.check_box :can_edit %> <%= permission.check_box :can_delete %> <% end %> <% f.fields_for :telephone do |child_form| %> <%= child_form.label :number %> <%= child_form.text_field :number %> <% end %> <% f.fields_for :addresses do |child_form| %> <%= child_form.label :name %> <%= child_form.text_field :name %> <% unless child_form.object.new_record? %> <%= child_form.check_box '_destroy' %> <%= child_form.label '_destroy', :caption => 'Remove' %> <% end %> <% end %> <% end %>