- From: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
- Date: Mon, 02 Nov 2009 19:36:30 +0100
- To: Steve Axthelm <steveax@pobox.com>
- CC: public-html@w3.org
Steve Axthelm On 09-11-02 17.42: > WebAIM released the results of their 2009 screenreader survey. > One of the questions I thought relevant to this issue: > > <http://webaim.org/projects/screenreadersurvey2/#images> > > "Some images, such as charts, diagrams, or comic strips, > are too > complex to describe in only a few words. If a long, detailed > description of these images is available, how would you > prefer to > have it presented to you?" > > > "There is no clear consensus in these responses. However, the > in-page options outweigh the options that place the longer > description on another page. Interestingly, the option of placing > the alternative on a separate page but having it announced > by the > screen reader, the current behavior of images with the longdesc > attribute, was a very unpopular option, second only to > being ignored > entirely." Thanks for notification about an interesting and relevant survey. Personally, I see the results as quite supportive of the way I see @longdesc. One thing to clarify first: a @longdesc does not per definition need point to another page. It could very well point to an element that follows directly after the image. I think we need to get this into both HTML 5 and ARIA! I miss a clear answer in your survey, on whether AT users also would have liked a way to "jump over" the the long description when/if they are satisfied with the short one. For example, one thing is that they can jump from the short/the image to a relevant description. However, those who prefer the long description to immediately follow the image/the short description, would they not like to know/be notified that this is the "this is just the long fallback for the image - hence you may skip if need be" ? An evaluation of the results: "On a separate page, available by following a link" together with "On a separate page, announced by and available to my screen reader" are very similar options, in my view, even if it is interesting that your readers preferred the least automatic variant - the link (and @longdesc is a link). Together they count for 181 voices, though, and thus become the largest group. These users effectively like to not be disturbed in their reading by the long description itself. I imagine that if some element is marked as "long description", and if the UA doesn't read such text unless the user asks it to do so, then it would not matter to these readers whether the description is in the page itself or on a separate page? "As text on the web page, immediately following the image" is the largest single group. It seems to be an answer that can be interpreted in many ways. Their motivation for this answer could be that they would like to get the long description without having to wait. It could also be motivated by normal expectations of a text: things that belong together should be close to one another. This has to do both with trusting the text and many other things. Also, a possible motivation for saying this could perhaps be that they prefer that the page looks the same for both blind and seeing. What is not clear to me, is whether those who answered like this would be against a way to jump over/ignore = identify the long description, both where it starts and where it ends ... I suppose not. The second highest score, "As optional text, available on the same page but only if I request it by following a link", could be said to cover the way I say that @longdesc can be used: to point to a place on the same page. However, I suppose that those who answered like this did not assume that the text *has* to be far away from the image. I suppose that they simply expect to activate the description by a simple click. The text could be close to the image, though. Thus their wish would not be very far from the "winning answer" - "As text on the web page, immediately following the image". My own thoughts: It seems to me that it would not have been so bad to have a specific "fallback element" - like <alt></alt>. Such a thing would be easy to ignore/identify, if I am right in that such ignoring/identification would be a good thjing. Such elements could could follow immediately after the IMG *and* it could also be accessible via a link (longdesc). (Sorry about the lack of pointer, but <alt></alt> has been suggested in this group earlier by others than me.) The advantage of <alt> over both aria-describedby and longdesc, is that it doesn't rely a link or idref pointer in another element - the element itself makes itself known as fallback/description/equivalent. The name of the element did not need to be <alt>. It could be something more telling, like <textequiv> or just <equiv> (for <equivalent>). Such elements did not need to always be hidden for sighted users, since sighted users may also need to identify a text as equivalent of a specific image. And in this regard: another thing I miss in your survey is that you had taken in the existence of <object> ... When <object> contains a static image, then inside that <object> is were the long description follows. Thus, when <object> is used, then the reader have every option to just jump over it, as the fallback have a clear beginning and a clear end. The only drawback I see w.r.t. use of <object> is that it currently doesn't offer any method for separating short and long fallback. -- leif halvard silli
Received on Monday, 2 November 2009 18:37:14 UTC