How to cycle banners without reloading page
 

I've got a set of banner ads on my forum set in to the header in a table and utilizing the 'random' feature to show a new banner when people reload a page or go to a new page.

What I'd like to do is have the banners in each cell of the table randomly cycle through on a time frame without reloading the page or going to a new page.
The tricky part is I'd like it to do this without moving the page within the browser so people don't get halfway trough a thread and have to scroll back down to where they were.

Is this possible?

Thanks!