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Re: providing a long description using the summary and details elements.

From: Steven Faulkner <faulkner.steve@gmail.com>
Date: Tue, 24 Aug 2010 16:04:09 +0100
Message-ID: <AANLkTingBXaMzA=m3kD4SP550aKrXPS=s20sWW0EtSZG@mail.gmail.com>
To: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
Cc: HTMLWG WG <public-html@w3.org>, HTML Accessibility Task Force <public-html-a11y@w3.org>
Hi Leif,

>I would add <details role="img"> as a requirement, whenever <details>
>is used to represent an image. Justification below.

it's not being used to represent an image its being used as a container for
a long text alternative.

>Making @longdesc a boolean like that, does not make sense to me, for
>several reasons. One thing is that it would go against how it is
>currently specced (and what about those bogus @longdescs out there?).
>But just as imporant: to rely on @longdesc like that, would be to not
>take advantage of <details role="img">,

i have suggested that
" longdesc attribute with URL value (longdesc="URL") provided for backwards
compatibility (suggest deprecated in HTML5)"

also
">    - use of longdesc attribute on image provides indication to browser/AT
>    that details/summary is being used for the specific purpose of
>    providing a long description."

how many bogus longdesc are there to be found in <summary> elements?

>One thing is that it would go against how it is currently specced

how is that an argument?

>But just as imporant: to rely on @longdesc like that, would be to not
>take advantage of <details role="img">,

I was trying to provide a native HTML5 method without recourse to ARIA,
besides i don't agree that it should be role="img".
>If the <details/> element has role="img", then everything outside the
><summary/> element naturally becomes the long description of what is
>summarized in the <summary/> element. Hence, there would be no reason
>to introduce @longdesc as some kind of boolean signal - such a thing
>would only be redundant. (And sometimes even incorrect - imaging if
>both @alt and text outside the @alt makes up the <summary/> text.)

As i said I don't agree that the details element should have a  role="img".

your code example:
<details role="img">
 <summary><img longdesc="link" alt="Short desc"></summary>
 <a href="link">long desc link</a>
</details>

problem with this is that everything inside the details element is guven a
role="img"
so the summary element, which will probablyu be exposed as a button to AT
will become an image, so will the link.

>Suggestion: the ARIA equivalent of role="iframe".
there is none, and again I would like to see a native solution, rather than
one that requires the addition of ARIA.

>One of the @longdesc use cases in
HTML4, is providing information about an iframe element.

this may have been useful in the earley days when AT did not support
<iframes>, to be honest I have never had cause to recommend using longdesc
on an iframe.

regards
stevef

On 24 August 2010 15:24, Leif Halvard Silli <
xn--mlform-iua@xn--mlform-iua.no> wrote:

> Steven Faulkner, Tue, 24 Aug 2010 12:15:12 +0100:
> > remailing with example code sans extraneous role and tabindex code:
>
> > an idea: using the summary /details elements to provide a long
> > description for an image:
> >
> >    - image goes in the <summary>
> >    - long description in <details>
>
> I would add <details role="img"> as a requirement, whenever <details>
> is used to represent an image. Justification below.
>
> >    - use of longdesc attribute on image provides indication to browser/AT
> >    that details/summary is being used for the specific purpose of
> >    providing a long description.
> >    - longdesc attribute with URL value (longdesc="URL") provided for
> >    backwards compatibility (suggest deprecated in HTML5)
>
> I'll leave the deprecation problem till later ...
>
> >    - longdesc attribute without an URL "longdesc" be specced as an
> >    indicator that a long description is present when image is sole
> >    content of the summary element.
>
> Making @longdesc a boolean like that, does not make sense to me, for
> several reasons. One thing is that it would go against how it is
> currently specced (and what about those bogus @longdescs out there?).
> But just as imporant: to rely on @longdesc like that, would be to not
> take advantage of <details role="img">,
>
> If the <details/> element has role="img", then everything outside the
> <summary/> element naturally becomes the long description of what is
> summarized in the <summary/> element. Hence, there would be no reason
> to introduce @longdesc as some kind of boolean signal - such a thing
> would only be redundant. (And sometimes even incorrect - imaging if
> both @alt and text outside the @alt makes up the <summary/> text.)
>
> Thus, the only valid use of @longdesc should be for backward
> compatibility for user agents which do not support the ARIA and
> <details>.
>
> >  example code:
> >
> > <details>
> >   <summary ><img src="images/table.gif" alt="Average rainfall in
> > millimetres by country and season." width="407" height="341"
> > longdesc="details.html#table"></summary>
> >
> > <table border="1" id="table"><caption>Rainfall in millimetres by Country
> > and Season.</caption><tr> <td></td><th scope="col">UK</th><th
> > scope="col">Japan</th><th scope="col">Australia</th></tr><tr> <th
> > scope="row">Spring</th><td>5.5</td><td>2.4</td><td>2</td></tr><tr> <th
> > scope="row">Summer</th><td>4.5</td><td>3.4</td><td>2</td></tr><tr> <th
> > scope="row">Autumn</th><td>3.5</td><td>1.8</td><td>1.5</td></tr><tr> <th
> > scope="row">Winter</th><td>1.5</td><td>1.2</td><td>1</td></tr></table>
> >
> > </details>
>
> Only thing I'm missing is <details role="img">.
>
>  [ snip ]
> > resolves issues of:
> >
> >    - providing *standardized* method for a programnmatically associated
> >    long description
> >    - provides it inline next to the image
> >    - only displayed on user request
> >    - does not clutter design (note example does not a disclosure triangle
> >    as is suggested for details/summary in spec, but this would not
> clutter
> >    desigh , i don't think)
> >    - deprecates current longdesc use, but provides for backwards compat
> >    and continued use of longdesc attribute
>
> +1 for deprecation if an equivalent or better way can be specced - and
> this method at least have potential.
>
> >    - details could conatin a.n <iframe> to display long descriptions
> >    external to the page.
> >    - long desc available to anybody who wants it.
>
> Let us focus on the simplest replication of the @longdesc feature ...
> Then this should be both back- and forward compatible:
>
> <details role="img">
>  <summary><img longdesc="link" alt="Short desc"></summary>
>  <a href="link">long desc link</a>
> </details>
>
> (The only problem we have, is that <details/> is a block element. This
> could be solved by wrapping it inside <object/>, though, provided that
> HTML5 would allow what HTML4 allows.)
>
> Regarding what you say about iframe: One of the @longdesc use cases in
> HTML4, is providing information about an iframe element. However, what
> you describe above, is how one could use an iframe as a long
> description container.
>
> While that is an interesting idea, how could the HTML4 use case be
> solved via <details/>? (HTML4 assumes that it is a burden for users of
> AT software want to know whether it is worth reading the iframe.)
>
> Suggestion: the ARIA equivalent of role="iframe". I'm in particular
> thinking about the situation when non-AT users do not need the
> <summary/>. How about the following:
>
> <details role="iframe">
>  <summary class="hidden-from-non-AT-GUI-users"
>          style="position:absolute;left:-100000cm;">
>          iframe description
>  </summary>
>  <iframe src="iframesrc">
>    <a href="iframesr">source doc</a>
>  </iframe>
> </details>
> --
> leif halvard silli
>



-- 
with regards

Steve Faulkner
Technical Director - TPG Europe
Director - Web Accessibility Tools Consortium

www.paciellogroup.com | www.wat-c.org
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Received on Tuesday, 24 August 2010 15:05:23 GMT

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