You're not running JavaScript. This site isn't intended for you, it's only a work-around for the people who don't know how to install an XMPP client on their computer. Go ahead and point your XMPP client to conference.nuegia.net. Running service discovery on that URL should give you a list of all the chatrooms hosted there which you can join or create.
Alternatively, if you do not wish to register for an XMPP account somewhere anonymous logon access is provided with a client that supports it such as Poezio. Just set it to connect anonymously to anon.nuegia.net. Hint: it's in the config file. Any client that supports anonymous logon will work, not just Poezio.
If you have reached this page in error and have not intentionally disabled JavaScript in your web browser, that means JavaScript broke again on your client. You can try refreshing the page to see if it works next time (It's a very finnicky and non-standardized technology, only the Google Chrome monopoly browser really works right with it) or better yet installing an actual XMPP client instead of trying to do everything through a web browser. There is a list of XMPP clients here and a beginner's guide to XMPP here. Here is an explanation of what XMPP is for the people who never heard of it before.