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Date: Mon, 28 Mar 2005 14:33:39 +0200
From: Sylvain Wallez <sylvain@apache.org>
Organization: Anyware Technologies
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Subject: Re: XMLHTTPRequest
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Philippe Guillard wrote:

> Hi
>
> I was happy/surprised to discover the xhr_carselector in 2.1.7 
> samples, and just want to get news about it (Sorry i can't access 
> Bugzilla today, and before didn't find much on bug 34077).
> I imagine this feature needs lots of work, maybe CForms re-work, so i 
> just wonder what is the situation.


The current situation is just this nice sample, but I had some 
background thinking about Ajax-ifying CForms for some times now and this 
is itching me more and more :-)

Basically, the idea is that widget stylings can be "ajax-aware". This 
means two things:
1 - the styling can send some events back to the form
2 - the various elements of the styling can be asynchronously updated,

The first item can be bound to the fact that a widget has an 
on-value-changed or on-action event handler, sending form values back to 
the server using XHR, and waiting for some update actions from the server.

When receiving an XHR-originated post, the form tracks all changes made 
to widgets as a reaction to this post (i.e. 
values/selection-lists/labels/errors/repeater-sizes, etc) and sends back 
this event list to the client (we will need a special generator for this).

The client sends these changes to the individual widget stylings in the 
page, which updates the display.

If some non-ajax-enabled styling needs to be updated (e.g. a repeater 
table), then a full page reload is triggered. This allows for the 
coexistence of "passive" stylings (the current ones) and ajax-aware 
stylings in a single page.

Just some rough ideas for now...

Sylvain

-- 
Sylvain Wallez                        Anyware Technologies
http://apache.org/~sylvain            http://anyware-tech.com
Apache Software Foundation Member     Research & Technology Director