Application helper to simplify the views in Rails3

form_error_helper

# app/helpers/application_helper.rb
def form_errors(form)
  if form.errors.any?
    content_tag :h2, "#{pluralize(form.errors.count, 'error')} prohibited this #{form.class} from being saved:" 
    content_tag :ul
    form.errors.full_messages.each do |msg|
      content_tag :li, msg
    end
  end
end


# View
= form_errors(@idea)