Producing web pages
* HTML CSS DHTML XHTML A to Z of tags        Accessibility          Design

8.1 Make programmatic elements directly accessible or compatible with assistive technologies

Make sure that the user interface follows the principles of accessible design: device-independent access to functionality, keyboard operability, and self-voicing etc. Failing this, an accessible alternative should be included in the HTML pages describing the function of the elements and providing an equivalent function.