After reading http://api.rubyonrails.org/classes/ActionView/Helpers/PrototypeHelper.html I just can't seem to find what I'm looking for. I have a simplistic model that deletes the oldest message after the list of messages reaches 24, the model is this simple:

class Message < ActiveRecord::Base
  after_create :destroy_old_messages
  protected
  def destroy_old_messages
    messages = Message.all(:order => 'updated_at DESC')
    messages[24..-1].each {|p| p.destroy } if messages.size >= 24
  end
end

There is a message form below the list of messages which is used to add new messages. I'm using Prototype/RJS to add new messages to the top of the list. create.rjs:

page.insert_html :top, :messages, :partial => @message
page[@message].visual_effect :grow
#page[dom_id(@messages)].replace :partial => @message
page[:message_form].reset

My index.html.erb is very simple:

<div id="messages">
  <%= render :partial => @messages %>
</div>
<%= render :partial => "message_form" %>

When new messages are added they appear just fine, but when the 24 message limit has been reached it just keeps adding messages and doesn't remove the old ones. Ideally I'd like them to fade out as the new ones are added, but they can just disappear. The commented line in create.rjs actually works, it removes the expired message but I lose the visual effect when adding a new message. Does anyone have a suggestion on how to accomplish adding and removing messages from this simple list with effects for both? Help would be greatly appreciated. Thanks for reading. P.S.: would periodically_call_remote be helpful in this situation?