W3C home > Mailing lists > Public > www-style@w3.org > June 2008

Re: WebKit now supports CSS Variables

From: Maciej Stachowiak <mjs@apple.com>
Date: Thu, 26 Jun 2008 12:55:47 -0700
Cc: Francois Remy <fremycompany_pub@yahoo.fr>, CSS 3 W3C Group <www-style@w3.org>
Message-Id: <3B36AB60-923A-4805-8501-7ECC865E68AC@apple.com>
To: Boris Zbarsky <bzbarsky@MIT.EDU>


On Jun 24, 2008, at 9:01 PM, Boris Zbarsky wrote:

>
> Francois Remy wrote:
>> And there's no CSS or HTML specification that query to the browsers  
>> to have some progressive rendering.
>
> Perhaps not, but there is also no specification that requires  
> browser to not have:
>
>  * { display: none ! important }
>
> in their default user stylesheet.
>
> The fact is, progressive rendering is something users want: they  
> want to start reading the start of a long document before it's all  
> loaded.

I think we might be mixing up two different senses of "progressive  
rendering":

1) Rendering a document where the content has only partially loaded  
(some of the document markup or external content references like  
images), but all stylesheets have loaded so style is correct for the  
part that is rendered.

2) Rendering a document when there are still pending external  
stylesheet loads, so that content may render with incorrect style.


Users clearly want Type 1 Progressive Rendering and most browsers do  
it. But Type 2 is generally considered an undesirable artifact (Flash  
Of Unstyled Content) and usually only considered an acceptable  
tradeoff when waiting for style is likely to be slow (for example on  
mobile devices).

The sense of "progressive rendering" in the CSS Variables discussion  
is all about Type 2, since that is the only case affected by  
references to variables defined in other stylesheets which have not  
yet loaded. Though, as I explained, this isn't really significantly  
different from cascading with rules in other stylesheets that are not  
yet loaded, as far as Type 2 progressive rendering is concerned.

Regards,
Maciej
Received on Thursday, 26 June 2008 19:56:28 GMT

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