Introduction to
Web Design

Usability

Information
Architecture

Confirm
Accessibility

Accessibility
Exercise

Search Engine
Optimisation

Prepare Web-site Content

Create, Maintain
& Validate a Site

Accessibility Standards are checkpoints devised by W3C Standards and apply to everyone.

Each checkpoint has a priority level assigned by the Working Group based on the checkpoint's impact on accessibility.
[Priority 1]
A Web content developer must satisfy this checkpoint. Otherwise, one or more groups will find it impossible to access information in the document. Satisfying this checkpoint is a basic requirement for some groups to be able to use Web documents.
[Priority 2]
A Web content developer should satisfy this checkpoint. Otherwise, one or more groups will find it difficult to access information in the document. Satisfying this checkpoint will remove significant barriers to accessing Web documents.
[Priority 3]
A Web content developer may address this checkpoint. Otherwise, one or more groups will find it somewhat difficult to access information in the document. Satisfying this checkpoint will improve access to Web documents.

Priority 1 is the most significant and in general states;

1.1 Provide a text equivalent for every non-text element (e.g., via "alt", "longdesc", or in element content). This includes: images, graphical representations of text (including symbols), image map regions, animations (e.g., animated GIFs), applets and programmatic objects, ascii art, frames, scripts, images used as list bullets, spacers, graphical buttons, sounds (played with or without user interaction), stand-alone audio files, audio tracks of video, and video.
Ref: http://www.w3.org/TR/WAI-WEBCONTENT/full-checklist.html

Why Accessibility Standards are Important.

Since the Web is expanding enormously and becoming the major source of information and entertainment, it is essential that people with disabilities are provided with as much access to the Web as possible. It is also a legal requirement.

User groups with particular accessibility requirements.

The visually impaired is an example of a user group with a particular accessibility requirement. The Web designer needs to design their site so that ‘Screen Reading” software can convey the meaning of every page. As outlined above in Priority 1, there needs to be a text equivalent for every non text element on the page.

Example of general legislated accessibility standards.

Section 508 requires that Federal agencies' electronic and information technology is accessible to people with disabilities. The Center for Information Technology Accommodation (CITA), in the U.S. General Services Administration's Office of Governmentwide Policy, has been charged with the task of educating Federal employees and building the infrastructure necessary to support Section 508 implementation. Using this web site, Federal employees and the public can access resources for understanding and implementing the requirements of Section 508.