- From: Jason White <jasonw@ariel.ucs.unimelb.edu.au>
- Date: Tue, 15 Jun 1999 10:00:05 +1000 (AEST)
- To: Web Content Accessibility Guidelines <w3c-wai-gl@w3.org>
On Sun, 13 Jun 1999, Charles McCathieNevile wrote: > > Using style sheets is an HTML-specific techique for "Use methods which can > be over-ridden by the user to control presentation". Style sheets are definitely not HTML specific: both CSS and XSL are intended to apply to XML documents as well. Indeed, having an appropriate medium-specific style sheet for one's output device is even more important in the case of XML document types, where no reasonable default rendering can be supplied by the user agent. Regarding the importance of using the latest W3C specifications, I can think of several cases where there are specific access advantages, including: (1) HTML 4.0 compared with earlier versions; (2) CSS 2 positioning; (3) MathML as opposed to the use of images; (4) Smil as opposed to other multimedia formats that do not include access features. The access benefits of HTML 4.0 and CSS 2 are described in detail in relevant WAI publications, and there are similar advantages to be gained from the other formats mentioned. I think these benefits are so significant that checkpoint 11.1 deserves its priority 2 rating. In relation to PDF, one might be able to achieve Level A conformance in some circumstances using existing conversion technologies, provided that there are no multimedia objects in the PDF file and that the conversion software correctly determines the reading order of the document. However, PDF versions 1.2 and earlier do not support any genuine separation of content from presentation, and the conversion process is thus necessarily limited. PDF 1.3, with its support for a true structural tree, will resolve these drawbacks once it has been implemented by both authoring tools and conversion software. For the present, I fully support the existing checkpoint: properly structured HTML documents must be provided alongside any proprietary document formats that are to be used.
Received on Monday, 14 June 1999 20:00:14 UTC