Fitting Ext JS into the Rails architecture

When you start building your first Ext JS page into your Rails application, you certainly will wonder where to put the Javascript code.
Instead of just creating a javascript file such as posts_show.js in your public/javascript directory, here is a more elegant way for adding Ext JS pages to your Rails (2.0.2!) project:

# app/controllers/post_controller.rb

def show
  @post = Post.find params[:id]

  respond_to do |format|
    format.html { render :layout => "extjs" } # *
    format.js
  end  
end

# *) special extjs layout which includes the required extjs files,
#    in case you have a different default layout for non-Ext JS pages 


# app/posts/show.html.erb

<%= javascript_include_tag formatted_post_path(@post, :js) %>

# app/posts/show.js.erb

Ext.onReady(function(){
  // your ext js javascript code here
  // because this file is rendered via the erb renderer,
  // you can add ruby code such as:
  alert('<%= @post.title %>');
});