It sounds like you need something running on the client side that can detect those changes, and push the changes back to the server side. I would guess that you need to look into AJAX. Microsoft has implemented Ajax support in ASP.NET 2.0 with something called Atlas. You might look that up to see if it can provide the functionality you're looking for. I haven't done anything with Ajax yet but it looks very interesting.
School of Medicine
University of Missouri Columbia