[Answered ]-Chat popup using Django + Jquery

Check out the accepted answer on this post:

How does Facebook chat avoid continuous polling of the server?

I think the Comet technique mentioned here would be best for your situation and could help you to avoid constant AJAX polling.

You could set up a Django view that worked as a client to a chat server, constantly listening, then it could close its connection and send the response to the browser (the hanging AJAX request) whenever a new event is received from the chat server.

You might want to try using jQuery UI Chatbox Plugin. It provides a widget and is easy to integrate.
http://www.cs.illinois.edu/homes/wenpu1/chatbox.html