<%= error_messages_for("forum_post") %> <%= simple_form_for(@forum_post) do |f| %> <% unless @forum_post.new_record? %> <%= f.input :topic_id, :as => :hidden %> <% end %> <%= f.input :body %> <%= f.button :submit, "Submit" %> <%= f.button :submit, "Preview" %> <% end %>