Refreshing a form without resetting it?

Hi,
I am using php to spit out a list from my database, each item in the list has check boxes next to it. I need to refresh this page ever 20 seconds to update the list, but I dont want the check boxes to reset when the page is refreshed, how might I accomplish this?
Any help would be much appreciated. thank you.

One idea might be to submit the page instead of refreshing it every 20 seconds.

That way you can figure out what check boxes are selected as they will be submitted as parameters.

When you re-create the page, simply set 'checked=true' for all the checkboxes that were ticked.