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Re: Choosing name for XML serialization (Was: Re: HTML5 differences from HTML4 editor's draft (XHTML5 and XHTML2))

From: Ian Hickson <ian@hixie.ch>
Date: Mon, 25 Jun 2007 18:58:51 +0000 (UTC)
To: Mark Birbeck <mark.birbeck@x-port.net>
Cc: Julian Reschke <julian.reschke@gmx.de>, Maciej Stachowiak <mjs@apple.com>, HTML WG <public-html@w3.org>
Message-ID: <Pine.LNX.4.64.0706251852220.14519@dhalsim.dreamhost.com>

On Mon, 25 Jun 2007, Mark Birbeck wrote:
> 
> But anyway, what about the other side of the equation? What about 
> authors who use 'video' in a document, which finds its way to an older 
> browser? There is nothing that can be done here within the language--a 
> problem for both HTML 5 and XTML 2.

All the radically new features of HTML5 (<video>, <audio>, <canvas>, 
<event-source>) are designed in such a way that they have a fallback 
mechanism. This mechanism can be used to display alternative content for 
legacy UAs, in the same way that <object> has always had a way to fallback 
to alternative content; or it can be bypassed by script solutions, for 
example Google has implemented <canvas> in script so that it can be used 
with IE6 and IE7 despite their lack of <canvas> support.

The less radically new features -- e.g. all the new form controls, 
<datalist>, <menu>, <datagrid>, etc -- are designed in such a way that in 
legacy UAs they will still be usable, just less feature-rich.

There is a lot that can be done to design a language's new features in a 
backwards-compatible way. It is difficult and careful work, but it is 
possible, and HTML5 goes to great lengths to ensure that it uses such 
techniques throughout. Several features have been designed and then 
removed from HTML5 after flaws in the fallback behaviour were pointed out. 
We have in fact been ruthless about ensuring this. Several of my favourite 
features were removed because we couldn't find a way to do them in a 
backwards-compatible way.

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Monday, 25 June 2007 19:13:47 GMT

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