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Re: headers attribute debate

From: Laura Carlson <laura.lee.carlson@gmail.com>
Date: Thu, 31 May 2007 14:06:00 -0500
Message-ID: <1c8dbcaa0705311206g2c68dc37j612dbb13c72d5678@mail.gmail.com>
To: wai-xtech@w3.org

For your information:

---------- Forwarded message ----------
From: Maciej Stachowiak <mjs@apple.com>
Subject: Re: headers attribute (was Re: Form elements)

On May 31, 2007, at 10:41 AM, Laura Carlson wrote:

> These questions are relevant not only to the headers debate, but also
> to the 'Moving forward' thread regarding reaching consensus and design
> principles/reviewing questions.
>
> Ben Boyle wrote [1]:
>
>> There seem enough cases here to warrant it's continued part in HTML.
>
> Anne van Kesteren wrote [2]:
>
>> The arguments for removing it are that the feature isn't widely used
>
> Thomas Broyer wrote [3]:
>
>> it has been proven that: headers= isn't used that much in the wild
>
> I asked about quantity of cases before [4] and didn't get a response.
> But I'll ask again. What is number of cases that proves a feature
> should be included or excluded from the spec? Also how is that number
> derived? What factors are taken into consideration?
>
> Thanks,
> Laura
>
> [1] http://lists.w3.org/Archives/Public/public-html/2007May/1262.html
> [2] http://lists.w3.org/Archives/Public/public-html/2007May/1249.html
> [3] http://lists.w3.org/Archives/Public/public-html/2007May/1259.html
> [4] http://lists.w3.org/Archives/Public/public-html/2007May/1144.html

I don't think there's a hard and fast number - it depends to some
extent on the nature of the feature. There are also two tests to meet:

1) Should it be required for implementations to support a given
feature? For pre-existing constructs (from past specs or in existing
browsers), this is based almost entirely on frequency of use, and
whether support affects interoperability.

2) Should it be allowed for use in conforming documents? This brings
additional considerations into the picture. In general, only
constructs with a valid use case should be allowed in conforming
documents. Those who are against including headers="" would argue
that nearly all the times you'd consider using it, scope="" will be
easier and less error-prone, so we should recommend that as a better
practice for authors. However, the counterbalance is that we want
authors to be able to make documents that degrade gracefully in
existing user agents without needlessly putting their documents out
of conformance.

So the key questions, in my opinion, are:

1) How much content is out there that uses headers="" correctly? Not
just tutorials but actual live web sites that use it on their table
markup. Bonus points if they use it correctly.

2) It's been stated that existing screen readers have better support
for headers="" than scope="". Can we quantify this? What are the most
popular screen readers and what is their approximate market share?
What is the user experience in each for a table marked up with
scope="", a table marked up with headers="", and a table that is not
annotated at all?

For features that are primarily handled by browsers rather than
assistive technologies, these are the kinds of questions we
investigate. The current use share breakdown is approximately 80% IE,
15% Firefox, 5% Safari, 1% Opera. Other browsers are all
significantly below 0.1%. Most people have all of these browsers
readily available so they can test things. So we tend to have good
information about how various constructs work in the browsers
actually used by users.

But I'd guess most of us don't even know what the top screen readers
are, and we certainly don't have access to do extensive testing. So
we'll need help gathering this kind of information.

Regards,
Maciej

---------- End Forwarded message ----------


-- 
Laura L. Carlson
http://www.d.umn.edu/goto/webdesign/
Received on Thursday, 31 May 2007 19:06:04 GMT

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