Re: device independent title attribute support in browsers and follow up question

Maciej Stachowiak, Fri, 06 May 2011 17:45:46 -0700:
> On May 5, 2011, at 2:26 AM, Steve Faulkner wrote:

Hi Steve and Maciej,

>> Do any vendors have plans to follow webkit's lead and display the 
>> title attribute content in place of an image when the image is not 
>> rendered?
> 
> I'm not sure if this is intentional behavior or a bug.

Webkit is not alone: the text browsers Links, Elinks, W3m and Lynx all 
display @title when @alt is lacking.

Opera does not automatically display @title when @alt is lacking, but 
it is, via CSS, possible to make it do so.

> It definitely 
> is intentional that we expose title to assistive technologies, and 
> that consequently VoiceOver will use it when present for images that 
> lack an alt attribute. It is also intentional that alt does not 
> create a tooltip, 

More details, VoiceOver vs @title vs @alt:

	1) for normal <a> (anchor) element links, then if @title + 
    link text are 100% equal (from a 'plain text' perspective), then
    VoiceOver does not not read the @title attribute. 

	2) if @title and link text differ w.r.t. characters (white
    -space doesn't matter, it seems), then both @title and link text
    is read. 

	Due to 1) and 2), VoiceOver reads each of the following 5 links
    as 'foo. Foo.':

          <a href title=" foo. Foo. "></a>
          <a href title=" foo. Foo. "><img alt=" foo. Foo. "></a>
          <a href title=" foo. Foo. "       ><i> foo. Foo. </i></a>
          <a href title=" foo. "     ><img alt=" Foo. "></a>
          <a href title=" foo. "            ><i> Foo. </i></a>

    3), for  <area> (area) element links, then a bug in VoiceOver
    or in Webkit cause @alt to be ignored so that only @title is
    read. When there is no @title, then VoiceOver "repairs" for
    lack of link text (by starting to read the @href content).

ARIA vs VoiceOver:

	From ARIA 1.0's perspective, then @title is completely ignored, unless 
there is no alternative to using it. Thus, from an ARIA supporting AT's 
perspective, it does not seem correct to assume that @title isn't used. 
But from the other angle: when both @title and @alt are present, then 
@title seems to be completely ignored in ARIA.

ARIA's approach and VoiceOver's approach lead to same result when:

    1. @title and link text are present and are identical;
    2. or when @title is present but link text isn't present;

ARIA's approach and VoiceOver's approach lead to different result when:

   * there is a link text and a @title that differs from the link text.

Which means that it is - roughly speaking - only when @title is used 
according to HTML5's rules about "advisory content" that there actually 
is any difference between VoiceOver and ARIA.
-- 
Leif Halvard Silli

Received on Saturday, 7 May 2011 21:08:47 UTC