This page doesn't contain scripting and is just a simple HTML page to launch the applet and thus it is impossible to log in to the chat using a custom nickname, a default nickname will be used with a number on the end. This script is useful for testing purposes and chat rooms that allow only anonymous connections. It is recommended to use index-js.html or index-php.html instead or write one by yourself. You can (and should) customize this to suit your needs, beginning from removing this note and changing the channel name from #majik to your channel or make an input field for asking it. After you feel like your copy of Jicra is up and running on your website, you may want to submit it to the listing of Jicra's around the world on Jicra's homepage, if your chat room is public and you want to get few extra visitors.
Sorry, you don't seem to have Java 1.1 compatible browser.