- From: Ian Jacobs <ij@w3.org>
- Date: Wed, 22 Sep 1999 12:02:38 -0400
- To: w3c-wai-ua@w3.org
Hello, In the 27 August draft [1], applicable checkpoint is defined as follows: <BLOCKQUOTE> A checkpoint applies to a user agent unless: a * The checkpoint definition states explicitly that it only applies to a different class of user agent. * The checkpoint addresses a content type (script, image, video, sound, applets, etc.) that the user agent does not recognize. * The checkpoint refers to a content type that the user agent recognizes but does not support natively. * The checkpoint refers to the properties of an embedded object (e.g., video or animation rate) that may not be controlled or accessed by the user agent. </BLOCKQUOTE> I would like to change this definition as follows: The spirit of these guidelines is the following: If a user agent offers a functionality, it must ensure that all users have access to that functionality or an equivalent alternative. Thus, if the user agent supports keyboard input, it must support accessible keyboard input. If the user agent supports images, it must ensure access to each image or an alternative equivalent supplied by the author. If a user agent supports style sheets, it must implement the accessibility features of the style sheet language. If the user agent supports frames, it must ensure access to frame alternatives supplied by the author. Not all user agents support every content type, markup language feature, input or output device interface, etc. When a content type, feature, or device interface is not supported, checkpoints with requirements related to it do not apply to the user agent. Thus, if a user agent supports style sheets at all, all checkpoints related to style sheet accessibility apply. If a user agent does not support style sheets at all, the checkpoints do not apply. The applicability of checkpoints related to markup language features is measured similarly. If a user agent supports tables, it must support the accessibility features of the language related to tables (or images, or frames, or video, or links, etc.). The Techniques Document includes information about the accessibility features of W3C languages such as HTML, CSS, and SMIL. The following summarizes criteria for applicability. A checkpoint applies to a user agent unless: * The checkpoint definition states explicitly that it only applies to a different class of user agent. * The checkpoint includes requirements about a content type (script, image, video, sound, applets, etc.) that the user agent does not recognize at all. * The checkpoint includes requirements about a content type that the user agent recognizes but does not support natively. * The checkpoint refers to the properties of an embedded object (e.g., video or animation rate) that may not be controlled or accessed by the user agent. * The checkpoint includes requirements about an unsupported markup language or other technology (e.g., style sheets, mathematical markup language, synchronized multimedia, metadata description language, etc.) * The checkpoint refers to an unsupported input or output device interface. Note that if the interface is supported at all, it must be supported accessibly. - Ian [1] http://www.w3.org/WAI/UA/WAI-USERAGENT-19990827 -- Ian Jacobs (jacobs@w3.org) http://www.w3.org/People/Jacobs Tel/Fax: +1 212 684-1814 Cell: +1 917 450-8783
Received on Wednesday, 22 September 1999 12:03:03 UTC