Javascript Navigation?

Does anybody know how the navigation at newmind.co.uk is achieved - they use the same technique on all of their sites. When you rollover the tabs sub navigation appears is this divs stacked ontop of each other and then hidden. I have asked all over the internet either they dont know or dont want to tell. I need to know what i need to learn to achieve this - i dont have time to learn from scratch at the moment.

If anyone knows pleeease tell me. Thanks

You won’t even need javascript for this. Post a question in the CSS forum.