Day based image/text swapper

[Nilsy]

I need some script that will swap an image or text after seven days, it must be javascript as the websites are run on a php based cms.

The basic scene is the website is for a school that has a timetable that is based on a two week timetable and on the website the school has requested a feature that shows which week they are in, "week 1" or "week 2".

Any help with this will be greatly appreciated.

Thanks

Nils