Update onBlur or onChange

Helo: I¹m working on a form that I¹d like to have a feature that adds your total as items are selected. Currently, I¹ve got some javascript doing the job but it only works in ie, and besides, I¹d rather use php if possible. The current prototype form lives at http://www.seatthole.com/order2.php Can anyone tell me if there¹s a way to update the total at the bottom of the page in realtime as the user makes changes? Thanks... Django