Written by Joshue O Connor Friday, 20 August 2010 14:43
The future of an important mechanism allowing the creation of accessible images using HTML5 hangs in the balance after a working group decision to remove it from the specification - despite the recommendations of their own expert working group to keep it.
The longdesc attribute (@longdesc) is used as a long descriptor for images on webpages to help describe them in detail for blind and vision impaired people. The idea being that for most images, a short or terse description is all that is needed but in some cases there is need for a more verbose or longer description, this is where @longdesc steps up.
Traditionally, @longdesc has been little used and there are many cases where a short text description will suffice as an image description. However, there are use cases where a much more detailed long description is actually needed - such as for technical diagrams, complex images such as periodic tables and other scientific materials either used in industry or in education.
So how could a useful, if little used attribute get dropped from HTML5? Firstly some background. The Public HTML 5 working group list, is a busy place so in order to focus on issues relating to accessibility it was wisely decided to start a dedicated accessibility related working group.
The HTML Accessibility Task Force
The HTML Accessibility Task Force (HTML A11y TF) was formed as a partnership between the HTML 5 working group and the Protocols and Formats working group (PFWG), in the W3C. Its purpose is to “ensure that HTML 5 provides features to enable Web content to be accessible to people with disabilities”. It is where both accessibility experts from the PFWG provide input and architects from the HTML WG provide input on architectural goals and non-accessibility considerations.
A recommendation was made to the HTML5 WG that @longdesc be retained. This decision was reached after much deliberation via email and Face to face discussion, and presented as a candidate recommendation.
The recommendation was then dismissed by the WG chairs - despite the existence of an equivalent functional alternative – and @longdesc is no longer a part of HMTL 5.
Some of the main reasons for dropping @longdesc include:
The strongest argument against inclusion was the lack of use cases that clearly and directly support this specific feature of the language. The fact that @longdesc has little observable uptake amongst users reinforces this: all the evidence indicates that users don't see this feature to be compelling, and the lack of user demand has been noticed by implementers
Chicken and Egg?
To some degree, I can understand why they came to the above conclusion, because when looking at the Web in toto pretty much all accessibility related functionally can look relatively very underused. What is spurious however is to state reasoning that there is little uptake amongst users, as the end user will only interact to what designers and authors put online in the first place, and it can be argued that only over time is awareness slowly increasing about Web Standards, best practice and how to support accessibility in Web design and development work. So this argument is a little chicken-and-egg.
Misuse of @longdesc?
Also another rational for @longdesc's discontinuation is that the content of many images containing @longdesc may be bogus. For me, this is not a very solid reason to discontinue this or any other attribute. More so when it is actually useful for people with disabilities. When needed the functionality should be there, available to the developer. The developer should not be censored nor or people with disabilities penalised due to legacy misuse.
No real alternative
Contrary to what the chairs of the HTML5 WG state, there are no real functional alternatives. What is cited as a replacement for @longdesc is ‘
aria-describedby’ however this is not a functional replacement as it is only an ID fragment identifier and not a fully functional replacement (this may be the case in future with ARIA 2.0 but it just isn’t at this point). Also the working group has stated a preference for native solutions (which @longdesc is).
FIGURE is maybe the closest functional equivalent but its functionality is closer to @alt or the
@longdesc is also mandated for those who with to comply with Section 508, the WAI guidelines and more as Laura Carlson from the University of Minnesota Duluth points out in a reply to the working group:
Longdesc is a technique recommended in both the WAI guidelines and the Section 508 standards. Standards issued by the Access Board under Section 508 of the Rehabilitation Act cover access to electronic and information technology procured by United States Federal agencies. One example: longdesc is an official part of United States Postal Service policy. It has also trickled down to States and State agencies. For instance, longdesc is a recommended solution in many University Web Standards like the University of Minnesota. Longdesc is part of Dutch Accessibility Law (section R-pd.7.3) Translation: "Do not use d-links on government websites. The use of longdesc (long description) attribute is preferred if the alternative text in the alt attribute is inadequate for understanding the information in the image.
So where next? There is currently an appeal to the Director of the W3C as well as couple of potential Formal Objections (which are both extreme measures but illustrate how serious the issue is). If the appeal is successful then @longdesc may be reinstated, either that or the engineers come up with a better solution, that is backwards compatible, that fits into the expectations of users and follows an establish user interaction pattern and so on. Actually @longdesc already does that, so why not just re-instate it?