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Re: danger of null value for summary attribute [Re: fear of "invisible metadata"]

From: Joshue O Connor <joshue.oconnor@cfit.ie>
Date: Fri, 29 Jun 2007 15:59:26 +0100
Message-ID: <46851E4E.1090908@cfit.ie>
Cc: public-html@w3.org

Gregory J. Rosmaita wrote:
>> a null value for summary defeats the entire purpose of alerting the 
>> user who cannot process the table at all or in toto, how the table 
>> is laid out, what it describes, etc.

If we are talking about layout tables - I don't know if I agree with you
on this one Gregory. For a start layout tables are not to be 'processed'
by the user as such, they act, as invisible (to sighted users anyway)
scaffolding for content. For screen reader users, they appear in a
different way and are certainly more visible to the user via the screen
reader with the tables purpose etc being announced by using @summary etc
when used. I guess in the end it comes down to preference, some screen
reader users (like yourself) may prefer @summary="This is a layout
table", and thats fine - whereas others maybe do not want that
information at all when the table is announced, especially if there are
lots of nested tables for instance etc, they may already know that it is
a layout table unless the author has added some info via @summary etc to
explicitly state otherwise. In most instances  it if far more important
that the content of a site that uses layout tables is marked up
correctly and then they user can get to where they want to go regardless
of the layout method. Sure, it's a pain when there are a lot of tables
used for layout and I am not for a moment suggesting it as a *good* way
of doing things.

By all means say @summary='This is a layout table' (and I suggest this
to clients who do use tables for layout) but also I guess (and I am new
to the idea of giving the summary attribute a null value) using
@summary="" could be a quicker way the user agent ignoring the table if
used for layout as it has no informative value. I guess however, this is
a moot point as they shouldn't be used for layout anyway and you are
certainly right that there is nothing wrong with announcing that it is a
layout table. I am just curious about possible applications of the null
@summary, as Craig also mentions in his post.

Craig Francis said:
> In the same way that adding an @alt to an <img>, with the content "This is a spacer image" - which I hope no-one does.

Absolutely but I'd suggest that what Gregory is saying about using
@summary='this is a layout table' is an instance where it is more useful
to inform the user that it is a table as the screen reader will pick up
the table and not ignore it even if it has a null @summary value AFAIK.
(I did some tests but am experiencing some graphic card weirdness at the
moment and don't trust my screen reader output, long story).

Ben Boyle said:
> I decided I'm pretty happy with what
> table@summary and table/caption offer today: 


> Personally I would omit @summary in favour of brevity; trusting in
> screen readers and their users to cope with the table structure (using
> good thead/th elements to help with that naturally). 

I would not sacrifice @summary just because you can use headers/id or
thead/th elements.

1) The summary attribute is really easy for authors to apply and not
make a balls of it.
2) See 1).

Received on Friday, 29 June 2007 14:59:52 UTC

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