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Re: Preload for <section>

From: Tantek Çelik <tantek@cs.stanford.edu>
Date: Thu, 26 Sep 2002 11:16:47 -0700
To: "C.Bottelier" <c.bottelier@itsec.nl>, Micho <MichoKest@terra.es>
Cc: <www-html@w3.org>, W3C CSS List <www-style@w3.org>
Message-ID: <B9B89D1E.18405%tantek@cs.stanford.edu>

On 9/26/02 6:02 AM, "C.Bottelier" <c.bottelier@ITsec.nl> wrote:

> 
> 
> Micho wrote:
>> I would be an easy to implement and usefull attribute, as when defining big
>> presentational elements they take a long time to load, producing changes in
>> the page while it's loading. This way (by displaying a 'loading' text or by
>> not displaying nothing at all until it's fully loaded), presentation could
>> be improved, somehow acting as flash's preloaders.
> 
> We have to consider a few things here:
> - User agents that do not understand the attribute (yet) should
>  still be able to render the page correctly
> - Documents using the attribute should still be able to be liniarized
>  without compromising delivered content.
> - When the document is served over a slow line and the author has
> chosen
>  not to show anything until the page has loaded completely, the user
>  could / would get the impression the document is empty.
> - when should the preload be replaced with the real content. (Regarding
>  refreshes of contents using scripting, animations, etc...)
> - Is it necessary to 'hide' changes produced by loading, or is this
>  *always* a side effect of bad design?
> 
> Christian Bottelier
> 

[crossposting www-style to move discussion there, since this about
presentation].

About four years ago I proposed a mechanism for authors to control the
presentation of elements while "loading":

 http://www.w3.org/Style/Group/1998/09/progrend-19980930

(W3C Member only link)

Essentially it consisted of a new pseudo-element ":partial" which permitted
the author to style how an element should be displayed while it was only
partially available, e.g.:

 section:partial { visibility:hidden }

would hide a section element until it was fully loaded.

As with all CSS mechanisms, users (such as those with slow connections) can
easily override author settings by placing a rule like this in their user
style sheet:

 *:partial { visibility:visible ! important }

Another portion of the proposal was a mechanism for determining what to
display while the content was :partial, but that can pretty much just be
done with the "content" property, e.g.

 section:partial { content: "Loading section..." }

Which again, could be overridden by the user in a user style sheet if so
desired:

 *:partial { content:normal!important; visibility:visible!important }


If there is now broader interest in having this capability, I would be happy
to re-raise it in the CSS working group.

Tantek
Received on Thursday, 26 September 2002 14:43:33 GMT

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