change language when user visits domain.com#fr etc

Hi,

i have a site which has a language switcher on it.
It uses jquery-lang.js

it works fine, but now I need for it to change automatically when a user visits domain.com#fr etc.
I have no idea where to start on this.
Firstly I need to add the hash to the url #fr
then i need THAT to trigger the language change.

Any tips?

Thanks in advance
Andy