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Re: Write-up about semantics in HTML5 from A List Apart

From: Martin Atkins <mart@degeneration.co.uk>
Date: Wed, 07 Jan 2009 10:17:58 -0800
Message-ID: <4964F1D6.7090104@degeneration.co.uk>
To: public-html@w3.org

Julian Reschke wrote:
> 
> Ian Hickson wrote:
>> ...
>>> But in XML based languages you can extend the vocabulary, and this 
>>> you can't in HTML. At least not the way it's currently defined.
>>
>> Can you name a single unilateral extension to the HTML element 
>> vocabulary that was a positive step forward in the development of 
>> HTML? HTML is almost 20 years old now, and (despite this being 
>> non-conforming) it has had its element name vocabulary unilaterally 
>> extended many times. If being able to do this was ever going to be a 
>> good thing, we'd have seen it by now. Have we?
>> ...
> 
> Again, the "who" is not the problem. We discussed this before.
> 
> The problem is that even *if* a future W3C Working Group wants to add 
> new elements, a change to the HTML parsing spec will be required.
> 

I think this is the most important point.

It would be ideal if future versions of HTML would be parsable by todays 
parsers, even if they ultimately ignore elements they don't understand.

The best example of this is void elements that get parsed as non-void by 
legacy parsers; it is therefore not possible to use new void elements 
without breaking software that employs legacy parsers, since the entire 
tree after the new void element will be incorrect.

A solution to this has been offered in the form of having the <element/> 
form be treated as void for all unknown elements.

I get the impression that Ian thinks this cure is worse than the 
disease. It is true that some authors will go on writing <img> (without 
the slash) and then be surprised when HTML5's new void element <foo> 
requires a slash, or when <script /> doesn't work. It seems like this 
sort of thing could be address with warnings from a validator, though I 
concede that many authors don't employ validators and would go on 
producing funky markup.
Received on Wednesday, 7 January 2009 18:18:38 UTC

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