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Re: Support Existing Content

From: Anne van Kesteren <annevk@opera.com>
Date: Fri, 04 May 2007 13:30:11 +0200
To: "Julian Reschke" <julian.reschke@gmx.de>
Cc: "HTML WG" <public-html@w3.org>
Message-ID: <op.trsvklv164w2qv@id-c0020>

On Fri, 04 May 2007 13:09:30 +0200, Julian Reschke <julian.reschke@gmx.de>  
> But what's the point in defining an additional conformance class, if it  
> doesn't make any difference in practice? (Methinks this is exactly what  
> you said yourself just a few messages ago).

To allow for extensbility of the language in the future. By discouraging  
people from using non-conformant constructs we can in the future introduce  
some additional parsing rules for new elements, for instance.

This is comparable with how 'color:foobar' works in CSS. foobar is  
currently not a conforming value for the 'color' property. This  
discourages people from relying on 'color:foobar'. In the future the  
'color' property could get a value 'foobar' that does something new in a  
compatible way as older user agents will simply ignore it.

The other advantage of keeping the conformant class smaller in this  
particular case is to encourage authors to write documents that are  
backwards compatible with older user agents. Because relying on some of  
the specific quirks in the HTML5 parser algorithm might not guarentee  
that. The error handling has evolved over the years and some browsers may  
not recover in the same way as others currently.

Anne van Kesteren
Received on Friday, 4 May 2007 11:30:16 UTC

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