Update Panel Trigger

Hi, I've successfully in the past created update panels with triggers, so when a dropdown box is changed it updates the panel.

I've now changed a DropdownBox on a page to a TextBox, and attached a datepicker to the TextBox for users to select a date -http://jqueryui.com/datepicker/

How can I create a trigger so when a new date is selected it updates the panel with a trigger?

Many Thanks