W3C home > Mailing lists > Public > public-html@w3.org > February 2009

Re: summary="" in HTML5

From: Henri Sivonen <hsivonen@iki.fi>
Date: Tue, 24 Feb 2009 11:49:53 +0200
Cc: HTMLWG WG <public-html@w3.org>, W3C WAI-XTECH <wai-xtech@w3.org>, W3C WAI Protocols & Formats <w3c-wai-pf@w3.org>
Message-Id: <4921DF3F-FAF4-4EA0-B07C-AD8E6A2D8501@iki.fi>
To: Ian Hickson <ian@hixie.ch>
On Feb 24, 2009, at 04:54, Ian Hickson wrote:

> (Screen readers properly supporting the 'speech' media would
> significantly aid in making pages written by caring authors more
> accessible, since hacks like 'text-indent' would not be needed.)

Unlikely. While people who use a given rendering medium themselves may  
be able to produce styling that is more usable than the UA default,  
people who don't use a rendering medium themselves don't have the same  
experience as users who use the medium all the time and due to this  
lack of experience may well produce styling that is worse than UA  
default.

Given that non-blind Web authors (i.e. most authors) usually don't use  
a speech rendering as their primary Web browsing medium, chances are  
that more often than not, dabbling in speech styling wouldn't be very  
competent.

> I notice, though, that the arrow showing which direction the table is
> sorted in is included only in the CSS. When I turn off the CSS (e.g.
> because I'm viewing the page in Links, or in Firefox with "No Style"
> selected), there is no indication of the sort order.
>
> Effectively this table is _more_ accessible for non-visual users than
> visual users without CSS!

Although CSS is optional in theory, in practice for actually browsing  
the Web in a visual rendering mode, CSS is de facto required, so  
arguments rooted in CSS being optional for the visual medium are more  
principled than practical.

> This, to me, argues that the summary information shouldn't be hidden  
> in
> the summary="", but should be somewhere in flow, like the <caption>.
> Instead of:
>
>   summary="Search results sorted by title, ascending">
>
> ...it would be better to have:
>
>   <caption>Search results sorted by title, ascending</caption>
>
> The CSS could then be used to hide this information, e.g.:
>
>   caption { height: 0; overflow: hidden; }
>
> ...without hiding it from users who need it.

Seems like a lot of trouble for just Links/Lynx users.

> http://www.eia.doe.gov/cneaf/electricity/epm/table1_13_a.html
>
>   This entire table is non-conforming (it's a layout table), so it
>   doesn't matter if we allow summary="" for it or not. The table
>   shouldn't exist. No summary required. (This summary="" is inserted  
> by
>   script, no less.)

I am unable to locate a summary attribute on this page either using  
View Source or Firebug. The following comment is about your remark  
more generally:

Layout tables are a cat that is totally out of the bag. Saying that  
layout tables a non-conforming doesn't properly pave this cowpath in  
an accessible way. Rather than trying to define layout tables out of  
existence, it would be more useful to define how to distinguish them  
from tables of actual tabular data.

Two syntaxes already have been invented for allowing authors flag a  
table as a layout table: summary="" (the empty string as the value)  
and role="presentation". Furthermore, JAWS (reportedly) and Gecko  
(from source code appearances[1]) already have heuristics for guessing  
if a table is a layout table.

I think it would be more practically useful to define authoring syntax  
for flagging layout tables and processing for determining which tables  
are layout tables than to categorically say that tables mustn't be  
used for layout. After all, the claimed accessibility harm of layout  
tables is not there if layout tables aren't presented as tables to AT  
users.

[1] http://mxr.mozilla.org/mozilla-central/source/accessible/src/html/nsHTMLTableAccessible.cpp#1029
-- 
Henri Sivonen
hsivonen@iki.fi
http://hsivonen.iki.fi/
Received on Tuesday, 24 February 2009 09:50:44 GMT

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