"Ian Hickson" <[EMAIL PROTECTED]>
> Could you elaborate on this backwards compatibility problem?
Sure, if authors go
.post() -> update UI to indicate something's started happening
event.onprogress -> indicate progress
event.onprogress (complete) -> update UI to indicate things have finished
Then user agents which do not get progress events never see the complete
status reflected in the UI, however if the UI uses onload to indicate
things have finished then the script is compatible with images and XHR
in user agents today.
Oh I'm not suggesting we get rid of the 'load' event.
Never did I think you were.
If authors chose to
only target newer UAs that's an authoring problem, not a backwards
compatibility problem. But then authors can always make that kind of
mistake with new features.
The only way to avoid the mistake, is to have everything you do onprogress
(complete) also done in onload, there's no other way. If there was a use
case where you wish to do something between the 2 events then I've not
managed to come up with it. Remember I'm also only suggesting that MUST is
too strong a restriction - basically I'd've SHOULD'd your MUST's and MAY'd
your SHOULD's.
All I'm saying is that we should make the progress events useful enough
that you can make the entire progress UI updating with them (setting max
and value each time), instead of having to have three sets of code (one to
set the max, one to set the value, and one to set the 100% value).
You just agreed that authors will make mistakes if they do that, and given
that it's one line of code for people who want your behaviour in onload, I
believe it is far and away the easiest solution for authors. The line of
code is of course just dispatching the progress event that you want.
So long as we have good examples, showing the progress UI be enabled
before the events, updated by the events, then removed by the handler for
the existing 'load' event, we can easily foster backwards-compatible UI
that will work identically in old and new UAs with the exception of having
nice updating progress bars in the new UAs.
So you're relying on "examples" to change author behaviour - I believe that
has failed scripters to date and the WG is not chartered to create extensive
user tutorial material nor should it be the place. I do not believe it's a
sensible requirement when there are no use cases identified when getting
that full event.
Cheers,
Jim.
