I made a webchat with frames; an infinitely-loading top part for the text, and the bottom an input box that received 204 to not reload when you sent a message. I guess that was the most elegant way to do it in the IE4+ days.
The top part could also receive a small <script> that would reload the frame on the right, containing the user list. Fun times. Used it with a couple class mates around 2000 iirc.