Re: sXBL issue -- bindings getting notified when the bound element is inserted into a document

At 06:08 PM 3/22/2005 -0600, Boris Zbarsky wrote:

> Jon Ferraiolo wrote:
> > (1) Boris seems to be saying that in XBL2 a bound element will have 
> > different methods depending on whether it has been inserted into the 
> > document or not.
>
> No.  I am saying that I hope this does NOT end up the case.  I am also 
> saying that this IS the case in Mozilla XBL in some cases, and that this 
> causes a fair amount of grief.
>
> Further, I am saying that the best way to prevent this problem cropping up 
> in XBL2 is to consider binding attachment now, before it becomes 
> effectively set in stone by sXBL.

That would mean
 - binding must happen before element is ever accessed (e.g at parse time 
and in createElementNS or similar methods)
 - bindings cannot be changed through styling

That seems to go against the direction of XBL2. We cannot have both 
well-defined methods and dynamic binding attachment


> > I agree that it is likely that somehow or other XBL2 will allow bindings 
> > to define methods and DOM attributes for bound elements. Under that 
> > assumption, thinking ahead to XBL2, doesn't it make sense that these APIs 
> > would be available at the time the xbl:bound event is raised, no matter 
> > whether the bound element is inserted into the document or not?
>
> Yes, agreed.  I have been operating on the assumption that this is the case.
>
> I am also operating on the assumption that people will want to use XBL2 to 
> create reusable bindings, which other developers will then use in their 
> pages. If this is not the case, then never mind me.

This is certainly the primary use that I have in mind.

Peter


> > (2) I still don't understand why the binding can't just register a 
> > DOMNodeInsertedIntoDocument listener on the bound element. I apologize 
> > for my inability to follow the discussion fully. Is it because 
> > DOMNodeInsertedIntoDocument results in common scenarios where the node 
> > might not be in the document anymore, which causes a large percentage of 
> > developers to have to put in a lot of checks into their scripting logic?
>
> I would not call the scenarios common.  But they're not particularly rare 
> either (there are certainly HTML pages out there that have <script> nodes 
> that remove themselves from the DOM, or tear down the entire DOM, when 
> they execute, which is more or less the same idea).  And if we accept my 
> premise that people are trying to create reusable bindings, then they need 
> to operate in a wide range of environments, which means they need to deal 
> with this issue.
>
> > Boris described a case where a binding is added at the same time that 
> > script is removing a node.
>
> No.  I described a case where the insertion of a node fires events or 
> scripts that remove it.
>
> > Is this a common case?
>
> Again, it happens....
>
> > I am wondering if we can at least warn developers about processing model 
> > complexities and suggest some techniques to avoid these complexities.
>
> You may want to view my suggestion as a proposal to simplify the 
> processing model so that developers need not deal with quite as much 
> complexity.
>
> -Boris