Chat on test7.operon.chat from the browser. Use any nickname, then identify with NickServ if you already have an account on this network.
Create an IRC account
Pick a nickname and join a channel. You can move around later with /join.
/join
Use /join #channel, /msg NickServ IDENTIFY password, or type a regular message to talk in the current target.
/join #channel
/msg NickServ IDENTIFY password
The message pane stays contained and scrolls independently, so long sessions do not turn into one giant page.