I have this:

http://page-test.co.uk/tabs.php

Is it possible to have the tabs so they fit the complete width of the outer box (the bottom one being slighter bigger than the top one)?

Obviously this could be manually done, but I would like to have it so it automatically fills the width regardless of the width and regardless of the number of tabs (so no manual work needed every time I set one of these up).

Thanks for any help.