# File lib/action_view/helpers/form_options_helper.rb, line 436 def grouped_options_for_select(grouped_options, selected_key = nil, prompt = nil) body = '' body << content_tag(:option, prompt, :value => "") if prompt grouped_options = grouped_options.sort if grouped_options.is_a?(Hash) grouped_options.each do |group| body << content_tag(:optgroup, options_for_select(group[1], selected_key), :label => group[0]) end body end