gistfile1.rb

## Controller

def rate
    @book = Book.find(params[:id])
    @book.rate params[:rating].to_i
    render :update do |page|
      page.replace_html("rating", {:partial => "rate", :locals => {:rateable => @book}})
      page.show "success_rating"
    end
end

## Criar partial:

#erb (views/books/_rate.html.erb)

<%= render_ajax_rating rateable %>
<%= image_tag "icons/spinner.gif", :id => :spinner, :style => "display: none;" %>
<div id="success_rating" style="display:none;">
  Voto computado!
</div>

#haml (views/books/_rate.html.haml)

= render_ajax_rating rateable
= image_tag "icons/spinner.gif", :id => :spinner, :style => "display: none;"
%p.success#success_rating{:style => "display:none;"}
  Voto computado!

## Usar partial na view:

#erb

<div id="rating">
  <%= render :partial => "books/rate", :locals => { :rateable => @book } %>
</div>

#haml 

#rating
  render :partial => "books/rate", :locals => { :rateable => @book }