After 3 years working with Rails I’ve noticed that my controllers have a lot statements like this: def index ... render :partial => "_partial", :locals => { ... } if request.xhr? # or render :ajax_template if request.xhr? end

As for me it’s a duplication. The similar situation was in Rails 2 in responding with proper format. In Rails 3 this issue was solved with respond_to & respond_with methods. If you agree with me take a look to Rjax gem that solves problem with ajax response.