To get it to work in Firefox, you must download the Greasemonkey add-on, which can be found at this https://addons.mozilla.org/en-US/fir.../greasemonkey/.
Then you just go to this page http://userscripts.org/scripts/show/107159 ,and press install on the relevant button.
You must accept what has to be accepted, restart your browser, then the normal chat window will be available.
The script works, unfortunately not in Internet Explorer but in Firefox and Chrome.