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

Re: Caption@title instead of table@summary?

From: Maciej Stachowiak <mjs@apple.com>
Date: Wed, 18 Feb 2009 02:04:57 -0800
Cc: HTMLWG <public-html@w3.org>
Message-id: <1E2E123E-DD02-46D8-8C5C-0A86E4B64AFE@apple.com>
To: Leif Halvard Silli <lhs@malform.no>

On Feb 17, 2009, at 10:07 PM, Leif Halvard Silli wrote:

> This message investigate the option of replacing table@summary with  
> caption@title.
> The @title attribute is reserved for advicory information. But what  
> @title is supposed to advice about differs a bit from element to  
> element. For instance, for an anchor link (<a href="*">), the @title  
> attribute advices not on the content of the element, but on the  
> content of the link target - usually. For an <img>, the @title might  
> inform on who created the image.
> Hence, I wonder if the @title of the <caption> would be able to  
> replace @summary. After all, it seems reasonable to say that the  
> @title of a <caption> advices on what the <caption> is an caption  
> for. Thus, a table summary could fit there.

Interesting idea. I think the core tradeoff between <caption title="">  
and <table summary=""> is whether the additional information is  
accessible (in some way) to sighted users. One reason we have both  
title="" and alt="" on <img> is specifically to discourage UAs from  
displaying alt to sighted users, since then it tends to contain  
auxiliary information instead of replacement text. On the other hand,  
a table summary should actually be auxiliary information about the  
table - it doesn't need to fully replace the table because the table  
is still there to be navigated if the user desires.

I'm glad that you provided a list of pros and cons - that's really  
helpful when comparing different proposals.

  - Maciej

> Benefits of using @summary:
>   * All UAs support @title - extremely backwards compatible. Doesn't
>     require any CSS hoolahoops.
>   * Like @summary, @title ensures that the content is purely fast
>     accessible text.
>   * All users can easily view @title content (mouse hovering is the
>     typical way)
>   * Empty <caption> elements are hidden, but still visible in the DOM.
>   * Even empty <caption> elements can be made "visible" through
>     relatively simple CSS and thus become available for hovering even
>     for visuall user agents, so that @title content can be read even
>     when <caption> is empty.
>   * Could promote more use of (non-empty) <caption> elements, which
>     should benefit all users.
>   * The link between table summary and caption becomes clear.
>   * Avoids the problems of the (claimed) misused @summary
>   * Builds on common pattern, namely the use of the @title attribute
> AT software benefits and problems:
>   * Not each and every screen reader support @summary (Or am I wrong
>     there?)
>   * What about discoverability, eg when <caption> is empty?
> Visual UA issues:
>   * It is possible that some users would be annoyed by seeing the
>     @title content when hovering over <caption>.
> Semantic issues:
>   * Is <caption title=""> often used in the wild? My assumtion is that
>     it is not. Hence, we should be relatively free to use
>     caption@title for summaries.
>   * Perhaps one would need to specify how to use table@title versus
>     how to use caption@title.
> I'm sorry if I have presented something that has allready been  
> investigated. But I could not see this option in the wiki [1]
> [1] http://esw.w3.org/topic/HTML/SummaryForTABLE
> -- 
> leif halvard silli
Received on Wednesday, 18 February 2009 10:05:38 UTC

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