W3C home > Mailing lists > Public > public-html@w3.org > December 2008

Re: Comparison of Smart Headers and HTML5 (ACTION-85)

From: Ben Millard <cerbera@projectcerbera.com>
Date: Mon, 8 Dec 2008 13:19:57 -0000
Message-ID: <B7920EF8C6804B68B18CD24DF8042BE1@ben9xr3up2lv7v>
To: "Joshue O'Connor" <joshue.oconnor@cfit.ie>, "Lachlan Hunt" <lachlan.hunt@lachy.id.au>
Cc: "HTMLWG" <public-html@w3.org>, "WAI-XTECH" <wai-xtech@w3.org>

Joshue O Connor wrote:
> As an aside, I don't really see how what is being suggested is that 
> different what currently happens within HTML 4 [...].

HTML5:

* Defines what happens accurately and without ambiguity. (If you find 
anywhere this isn't the case, be sure to mention it!)
* Handles some cases which HTML4 definitely does not.
* Clarifies many things which HTML4 is vague about.
* Makes table accessibility a UA requirement. (In HTML4, supporting table 
accessibility features is optional.)

It's difficult to pin down "what currently happens within HTML4":

* How the various association mechanisms interact with each other is 
undefined.
* Exactly when does the automatic algorithm get used?
* Imprecise descriptions of the table model, such as what constitutes "a 
column".
* Conflicting descriptions of what influences specific features.

As a demo of these problems with HTML4, I tried to pin down exactly what is 
supposed to happen when an HTML4 table uses the scope attribute. In 
particular, when it is used on a cell with colspan, rowspan or both:

<http://projectcerbera.com/blog/2008/11/scope>

The conclusions in that article stick as strictly as possible to what HTML4 
says. But resolving the conflicts and gaps in HTML4 sometimes amounts to 
guesswork. Reasonable people can arrive at different conclusions. :)

Joshue O Connor wrote:
> If you can, could you please highlight for me (briefly) what the 
> differences/improvements are?


HTML5's biggest improvement is having a clear description of the table model 
with a unified header association algorithm to define how it all works 
together, imho. From this, you can assess what happens in any table much 
more precisely.

There's a note in my comparison document about why it doesn't compare HTML4 
to the more recent work:

[[[
HTML4 is not included due to ambiguities which become significant when 
assessing exactly what happens in genuine data tables.
]]]

-- 
Ben Millard
<http://projectcerbera.com/web/study/> 
Received on Monday, 8 December 2008 13:21:13 UTC

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