As we saw above, attribute values may be set during initialisation.
There are two other important ways to change them. One is by interaction
with the user. When the user submits a form or clicks on an imagemap,
the data will be sent to the server, which will split it up and route
each value to the appropriate instance. In general, this will change
value attributes, as defined
in the run-time library.
Attributes can also be updated by code-inserts, described in Section 2.10.