- From: Alan J. Flavell <flavell@a5.ph.gla.ac.uk>
- Date: Sun, 19 Aug 2001 15:31:00 +0100 (BST)
- To: Jonathan Chetwynd <j.chetwynd@btinternet.com>
- cc: WAI Guidelines List <w3c-wai-gl@w3.org>
On Fri, 17 Aug 2001, Jonathan Chetwynd wrote: > This does not mention links. > > If it is the case that alt should describe the image and title the link, do > we need to state this? Technically, the following parameters are available, in the situation that I think you are describing i.e an image acting as an anchor link: - the alt attribute of the <img ...> - the title attribute of the <img ...> (the longdesc is also available, and important in its way, but I don't think it's what we're talking about here) - the title attribute of the enclosing <a href=...> What needs to be discussed, and I've never seen this done in enough detail (and all the discussions I've seen have backed-off from analysing what the principles _should_ be, out of consideration for the presently-available implementations that people are using) would be: a) how, ideally, ought these parameters to be used? b) how, if these parameters were used ideally, ought client agents to present them to the user? It seems clear to me that the title attribute of the <a href=...> is for supplying additional information about what is to be found at the target of the link. This information could meaningful for all kinds of links, not only those which use <img ...> to implement them (and in fact the title attribute of the <a ...> element has been a feature of HTML since at least HTML2.0, long pre-dating the title attribute on HTML elements in general). The title attribute of the <img ...> would seem, logically, to be available for providing a brief description of the image itself, independent of the fact that this particular image is also serving as an anchor link. I guess my views on the alt attribute of the <img ..> are already well known: the detailed wording of any recommendation gets kicked around, but it's meant in general terms to serve as a text-mode _alternative_ for the _purpose_ of the image. If the image was primarily there to convey information, then the alt text should also be primarily there to convey that information. On the other hand, in the case where the image is primarily intended as a decorative link to another resource, the alt text should be designed to serve as a text-mode link to that resource, without diverting attention to incidental features of the particular decoration that was used (the img's title attribute is still available for that purpose). Do the usually-available client agents co-operate with this view of the intentions? In general I think we'd have to say "no", or rather, "only partially". For example, of the various attributes, the <a title=...> would seem to be of more importance to the user than the <img title=...> in this kind of situation, but the popular client agents will give the inner (img) markup priority over the outer (a href) markup. In fact if the img stands alone within the a href, then it seems impossible to persuade popular clients to display the title attribute of the a href, if the img also carries a title attribute. Only when the a href element contains both an img and some normal text, is it possible to see the title attribute of the a href - by hovering over the text. Sure, this is a description of the popular browsers, rather than of specialised accessibility agents. And for example with MSIE it's possible for the user to supply their own persistent scripts, which could analyze the document object and display features that are not normally exposed to the user. (The MSIE5 Web Accessories, IE5WA, illustrate some examples of what is possible in this regard). So, an admittedly unsatisfying and incomplete answer, but I hope it's somewhat helpful, nevertheless.
Received on Sunday, 19 August 2001 10:31:08 UTC