W3C home > Mailing lists > Public > www-forms-editor@w3.org > January 2003

Canceling notification events

From: Micah Dubinko <mdubinko@yahoo.com>
Date: Sat, 4 Jan 2003 21:06:15 -0800 (PST)
Message-ID: <20030105050615.96882.qmail@web9707.mail.yahoo.com>
To: www-forms-editor@w3.org

In the XForms CR, certain notification events are listed as cancelable:

xforms-activate
xforms-value-changing
xforms-value-changed
xforms-select
xforms-deselect
xforms-scroll-first
xforms-scroll-last
xforms-insert
xforms-delete

[the other 10 xforms-* notification events are not cancelable]

What does it mean for a notification event to be canceled? How have
implementers addressed cancelation of the above events? For instance,
does canceling xforms-value-changed cause the value to revert back to
what it was previously??

I suggest that events that are purely for notification should never be
cancelable, since canceling the event has no appreciable effect.

As a precedent for this approach, I point to section 1.6.4 of DOM Level
2 Events, Mutation Events, where it says:

"""It may be noted that none of the mutation events listed are
designated as cancelable. This stems from the fact that it is very
difficult to make use of existing DOM interfaces which cause document
modifications if any change to the document might or might not take
place due to cancellation of the related event."""

I further note that the XForms events for "Error Indications" are
uniformly non-cancelable, again since canceling the event would have no
noticeable effect.

If there are good reasons for the current approach, it would be good to
document them somewhere.

Thank you for your consideration,

.micah

=====
Find out what the fuss about XForms is all about. Full text of my book in-progress online at http://dubinko.info/writing/xforms/

__________________________________________________
Do you Yahoo!?
Yahoo! Mail Plus - Powerful. Affordable. Sign up now.
http://mailplus.yahoo.com
Received on Sunday, 5 January 2003 00:06:17 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Wednesday, 10 June 2009 18:12:12 GMT