Simple pattern for handling jquery js in rails

application.js

// public/javascripts/application.js
// JQUERY example

// Accepts ev.foo, ev.bar, ev.html
$(document).bind('some:event', function(ev) {
  // do something here
  $('some-div').html(ev.html);
});

prototype_ext.rb

# lib/extensions/prototype_ext.rb
# NEEDS to be required manually in rails app)
# Uses debug library from here: http://benalman.com/projects/javascript-debug-console-log/
# This is for jquery library but can be done with prototype as well (Rails 2)

module ActionView::Helpers::PrototypeHelper
  class JavaScriptGenerator
    module GeneratorMethods
      # will trigger a jquery custom event in order to cause
      # some externally defined javascript to occur
      #
      # event_name = "custom:event" (the event to trigger)
      # parameters = { :var => "value" } (the parameters to pass)
      #
      # example: page.trigger "custom:event"
      #
      def trigger(event_name, parameters={})
        parameters.reverse_merge!(:type => event_name)
        self << "$(document).trigger(#{parameters.to_json})"
        self << "debug.info('triggered', #{event_name.inspect}, #{parameters.to_json})" if Rails.env.development?
      end
    end
  end
end

some.js.rjs

# app/views/thing/some.js.rjs

# Jquery example
# This sends the necessary data to update the state
some_html = render(:partial => "foo")
page.trigger("some:event", :foo => 'bar', :bar => "baz", :html => some_html)