error_message_on (ActionView::Helpers::ActiveRecordHelper)

    # File lib/action_view/helpers/active_record_helper.rb, line 109
          def error_message_on(object, method, *args)
            options = args.extract_options!
            unless args.empty?
              ActiveSupport::Deprecation.warn('error_message_on takes an option hash instead of separate ' +
                'prepend_text, append_text, and css_class arguments', caller)

              options[:prepend_text] = args[0] || ''
              options[:append_text] = args[1] || ''
              options[:css_class] = args[2] || 'formError'
            end
            options.reverse_merge!(:prepend_text => '', :append_text => '', :css_class => 'formError')

            if (obj = (object.respond_to?(:errors) ? object : instance_variable_get("@#{object}"))) &&
              (errors = obj.errors.on(method))
              content_tag("div",
                "#{options[:prepend_text]}#{errors.is_a?(Array) ? errors.first : errors}#{options[:append_text]}",
                :class => options[:css_class]
              )
            else
              ''
            end
          end