- From: Jason White <jasonw@ariel.ucs.unimelb.edu.au>
- Date: Thu, 13 Jul 2000 10:05:45 +1000 (EST)
- To: Web Content Accessibility Guidelines <w3c-wai-gl@w3.org>
Over the weekend I wrote a draft reformulation of the Web Content Accessibility Guidelines which attempts to address many of the issues that have been considered by the working group since the publication of WCAG 1.0 as a W3C Recommendation. It should be emphasized that this draft builds upon, and generalizes, the requirements set forth in WCAG 1.0. It is being provided as the starting point for discussion, and has not been endorsed as an official working group draft. The responsibility, accordingly, for any errors or omissions is entirely mine. A text version of the draft is included below. The full HTML version is expected to be made available via the working group's web site shortly. As a final note, this is an outline only, and as a consequence many important explanations, qualifications and examples have not been included. Please review and comment. Draft text follows: Draft Reformulation of Web Content Accessibility Guidelines Introduction The following new terminology is proposed in this draft: 1: Principles These are the highest, most abstract general maxims of accessible design, from which the concrete requirements are derived. In effect, they serve as subject headings under which the guidelines are categorized. They correspond to what were called "guidelines" in WCAG 1.0. 2: Guidelines. These requirements are more specific and detailed than the general principles; however, they are not specific to any particular technology. Some of the requirements may be applicable only to a certain range of protocols or data representations (E.G. multimedia formats), but they are not restricted to the features or capabilities that may appertain to any particular, existing standard, specification or implementation. Guidelines in this sense sometimes correspond to "checkpoints" in WCAG 1.0, but only in those instances where the latter are expressed in general (rather than technology-specific) terms. 3: Checkpoints [not shown in this draft]. These are the technology-specific requirements, suitable for implementation by a content designer or authoring tool, which have been derived by applying the guidelines to a specific technology, whether it be a communication protocol, software interface, or a combination of markup and/or style languages. Checkpoints are non-normative, in that there may exist other, equally effective means of satisfying the requirements specified in the guidelines. However, proper application of the checkpoints is deemed to constitute a correct and adequate implementation of the guidelines. Stated differently, the checkpoints operate as sufficient, but not as necessary conditions for determining whether the guidelines have been followed. Principles and Guidelines Principle 1: Provide alternatives to auditory and visual presentations Guidelines 1. Provide a textual equivalent for every non-text (auditory or graphical) component of a web page or multimedia presentation. 2. Until user agents can automatically read aloud the text equivalent of a visual track, provide an auditory description of the important information of the visual track of a multimedia presentation. 3. For any time-based multimedia presentation (e.g., a movie or animation), synchronize equivalent alternatives (e.g., captions or auditory descriptions of the visual track) with the presentation. Principle 2: Separate content and structure from presentation, and ensure that significant structural or semantic distinctions are captured in explicit markup. Guidelines 1. Use markup languages properly and in accordance with specification. 2. Use style languages, where available, to control layout and presentation. 3. Where presentation is used to communicate distinctions of meaning or structure within the content, ensure, if possible, that semantic markup is also provided which conveys these distinctions equivalently. Note that the semantic and presentational markup corresponding to a document need not reside in the same file or logical resource; these guidelines mandate only that both must exist and be available to the user agent. 4. Do not rely on presentation alone (E.G. colour or font changes) to express semantic distinctions (this is a corollary of the preceding guideline). 5. Ensure that distinctions which are necessary or beneficial to the rendering of the content in different media (E.G. auditory or tactile) are reflected in the markup. For instance, use markup to identify changes in the natural language of a document, or to distinguish fragments of mathematical notation or computer program code from the surrounding text. Principle 3: Provide default presentations, while facilitating the application of user-specified presentations Guidelines 1. Specify one or more default presentations of the content, for example with style sheets, or by supplying pre-formatted versions which can be selected via content negotiation or explicit user requests. Where practicable, offer a variety of alternative presentations suited to different output devices. For example, provide style sheets relevant to high and low-resolution displays, printers and speech output systems. 2. To facilitate the application of user-supplied transformations and style rules, ensure that documents validate to the formal grammars of markup languages which are defined in published specifications, and which support the application of these guidelines. 3. When using style languages which support a "cascade" of authors' and users' preferences, ensure that style sheets are designed in such a way as to operate gracefully if partially overridden by the user agent. For example, specify lengths in relative rather than absolute units of measure. Principle 4: Design for ease of comprehension, browsing and navigation Guidelines 1. Use a consistent style of presentation in which the structural and semantic distinctions expressed in the markup, are associated with appropriate formatting conventions that enhance the readability and intelligibility of the content. 2. Provide clear and consistent navigation mechanisms throughout a web site. 3. Supply an overview of the general organization of a site or of a document which has been split into multiple, independent resources (E.G. in a map or table of contents). 4. Divide large blocks of information into more manageable groups where natural and appropriate. 5. If search functions are provided, enable different types of searches for different skill levels and preferences. 6. Place distinguishing information at the beginning of headings, paragraphs, lists, etc. 7. Use the clearest and simplest language appropriate for a site's content. 8. Supplement text with graphic or auditory presentations where they will facilitate comprehension of the content. 9. Use headings, labels and titles appropriately to identify structurally significant divisions within the content. Note that in addition to full, descriptive labels, it may also be appropriate, in designing complex structures such as tables and forms, to provide abbreviated labels which can be used when the content is rendered on small displays or via speech output. 10. Provide an overview or summary of highly structured materials, such as tables. 11. Define key terms, and provide expansions for abbreviations and acronyms, which should be identified using appropriate markup. Principle 5: Design user interfaces for device independence Guidelines These need to be reworked to take account of the separation between user interface logic and presentation which is provided by X-Forms. 1. Associate an explicit label with each user interface control. 2. Ensure that user interface controls are grouped logically. 3. Ensure that event handlers are device-independent. 4. Design user interfaces to be compatible with assistive technologies. Principle 6: Compensate for older technologies and missing or incompletely implemented features of user agents Guidelines 1. Make sure that web sites which use newer technologies transform gracefully. 2. Avoid causing content to blink or flicker. 3. Avoid causing pages to be refreshed or updated automatically. Any other interim measures which are considered to be of vital importance may be included here. Checkpoints without an obvious place in this scheme Checkpoint 2.2 from WCAG 1.0 doesn't seem to fit: 2.2 Ensure that foreground and background color combinations provide sufficient contrast when viewed by someone having color deficits or when viewed on a black and white screen. Most other checkpoints can be subsumed under the HTML/CSS technology-specific checklists, or have been incorporated within the generalized guidelines as presented above. Comments Draft prepared by [1]Jason White. Please direct comments to the working group mailing list at [2]w3c-wai-gl@w3.org. References 1. mailto:jasonw@ariel.ucs.unimelb.edu.au 2. mailto:w3c-wai-gl@w3.org
Received on Wednesday, 12 July 2000 20:07:09 UTC