The ``End session'' action link contains an OnSubmit. If the link
is clicked on, that code will be obeyed. It refers to one built-in
attribute, Root, as in localnamebase~getRoot, and
to one built-in method, deleteAndExpire. When called, this
deletes its instance and updates the server tables so that for a short
time afterwards, a ``session has expired'' page is sent back if the
user tries to access the session. This will eventually itself be deleted.