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

Re: summary="" in HTML5 ISSUE-32

From: Ian Hickson <ian@hixie.ch>
Date: Fri, 27 Feb 2009 01:16:58 +0000 (UTC)
To: Matt Morgan-May <mattmay@adobe.com>
Cc: HTMLWG <public-html@w3.org>
Message-ID: <Pine.LNX.4.62.0902270058170.8214@hixie.dreamhostps.com>
On Thu, 26 Feb 2009, Matt Morgan-May wrote:
> > 
> > We're not just removing it, we're replacing it with something that 
> > helps more users (<caption>).
> 
> ...which fewer authors will use, since it forces a visual 
> representation.

I think that the total number of pages that use <caption> in a useful way 
after <caption> has been advocated for for a decade would be higher than 
the total number of pages that use summary="" in a useful way today. 
However, that _is_ just an opinion and I don't know how to prove it either 
way.

In general though, I think it's clear that features that are visible to 
most authors have been used more appropriately than those that are not 
(e.g. href="" is used more correctly in general than cite="").


> No designer is going to redesign their navigation tables so that the 
> caption of "navigation" shows through.

Could you elaborate on this? What is a "navigation table"?


> > I don't agree with either of these statements. My position is just 
> > that there is data showing that summary="" as designed both fails to 
> > help disabled users (by being mostly bad data when used)
> 
> I looked at the data posted most recently, and I came to a different 
> conclusion. For one thing, summary="(null|whitespace)" is what we've 
> used to indicate layout tables for years. And as has been mentioned 
> today, the biggest real issue is the mistaken practice of stating 
> "layout" or "design", and assistive technology across the board has 
> heuristics to filter that out. You're basing your decision on a problem 
> that in practice does not exist.

Given Philip's data set, for instance:

   http://canvex.lazyilluminati.com/misc/summary-20090226.html

Could you point to a summary value that isn't bad?

There are a couple, maybe, but the vast majority fall into one or more of 
the following categories:

 1. Summaries for layout tables; those tables shouldn't be there in the 
    first place.

 2. Summaries that are actually better as captions.

 3. Keyword stuffing for abusing search engine ranking algorithms.

 4. Completely unhelpful text.


> > and hurts non-disabled users (by causing there to be information 
> > hidden from them when the attribute _is_ used in a way that helps 
> > disabled users).
> 
> ...except that to date, the content of the attribute is explicitly for 
> the benefit of non-visual users. Any analysis of the existing data in 
> coming to this conclusion is invalid, since visual users were never 
> intended to receive it.

That misses the point. The summary="" attribute might be intended only for 
non-sighted users, but that doesn't mean that it's ok for the information 
in it to be hidden from sighted users even when the information would be 
useful to them.

Consider the exact opposite case: <canvas> and <img> are intended only for 
sighted users. Does that mean that it's ok for the content in those 
elements to be hidden from non-sighted users? No! We have to convey the 
information from those elements to _all_ users, hence <canvas> fallback 
and alt="".

If summary="" is causing people to hide useful information from sighted 
users -- as Steven's data showed -- then we should find a way to encourage 
authors to expose the information to _all_ users. The HTML5 spec today 
does this using <caption>.

(The same applies to <canvas>, for instance. If having <canvas> causes 
authors to hide information from non-sighted users, which it seems to, 
then we should find some solution that exposes that data to non-sighted 
users somehow. Currently no such mechanism has been suggested, unlike the 
situation with summary=""/<caption>.)


> > The current proposal is to use <caption> instead of summary="", which 
> > should both improve the quality of the accessibility aids (since 
> > authors will _see_ their bad summaries and remove them if they're bad) 
> > and the make them universally accessible (since <caption> is 
> > media-independent).
> 
> That's interesting as a thought experiment, but not as a format 
> specification.

Why?


> > Existing pages with summary="" aren't affected. AT tools are still 
> > expected to support the summary="" attribute
> 
> Irrelevant. You don't get credit for not actively breaking HTML 4.01.

I'm not looking for credit, I'm trying to improve accessibility for end 
users.


> > and validators are expected to not report the presence of summary="" 
> > as a serious problem.
> 
> But it's still invalid markup. It's a distinction without a difference.

There is a difference, by definition. I agree that it is still invalid 
markup in HTML5 documents. That's intentional, to encourage people to use 
better mechanisms such as <caption>.


> > New pages that use <caption> wouldn't be any less accessible either.
> 
> Where's the proof of that?

The example for <caption> in the spec is one existence proof.

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Friday, 27 February 2009 01:18:26 GMT

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