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Introduction

Purpose

This document outlines design principles for creating accessible Web content. When these principles are ignored, individuals with disabilities may not be able to access the content at all, or they may be able to do so only with great difficulty. When these principles are employed, they also make Web content accessible to a variety of Web-enabled devices, such as phones, handheld devices, kiosks, network appliances. By making content accessible to a variety of devices, that content will also be accessible to people in a variety of situations.

The design principles in this document represent broad concepts that apply to all Web-based content. They are not specific to HTML, XML, or any other technology. This approach was taken so that the design principles could be applied to a variety of situations and technologies, including those that do not yet exist.

How to read this document

In order to facilitate understanding of the guidelines and to help people focus in on just the parts they need, the guidelines are presented as a set of interrelated documents. There are 3 layers to the guidelines information.

1 - Top layer - Overview of Design Principles, Guidelines, Success Criteria

The top layer is titled "Web Content Accessibility Guidelines 2.0" . It is the document you are currently reading. This document provides:

  1. An introduction

  2. The 4 major principles for accessibility (Perceivable, Operable, Understandable and Robust).

  3. The (non-technology-specific) guidelines (14 in total).

  4. Success criteria ( normative ), and definitions, benefits and examples (all non-normative) for each guideline

  5. An appendix containing definitions, references and other support information.

2 - Technology-specific Checklists

In addition to the general guidelines, there will be a series of technology-specific checklist documents. These documents will provide information on what is required when using different technologies in order to meet the WCAG 2.0 Working Draft.

Editorial Note : These checklists do not yet exist. At the present time, it is not clear if the checklists will be normative or non-normative. If checklists are non-normative, it is easier to update them. If checklists are normative, changes made to them alter the definition of conformance. However, it may be necessary to make checklists normative in order for the guidelines to be testable.

3 - Bottom layer - Technology-specific application information

The Techniques Documents will include code examples, screen shots, and other information specific to a technology. These documents will be non-normative. They will contain different strategies for meeting the requirements as well as the current preferred approaches where they exist. Examples include:

(Items above will become active links as the corresponding Working Drafts are published)

Audience

These guidelines have been written to meet the needs of many different audiences from policy makers, to managers, to those who create Web content, to those who write the code. Every attempt has been made to make the document as readable and usable as possible while still retaining the accuracy and clarity needed in a technical specification. For first time users, the work of the Education and Outreach Working Group of the Web Accessibility Initiative is highly recommended.

Scope

These guidelines cover a wide range of issues and recommendations for making Web content more accessible. They include recommendations to make content accessible and usable by people with a full range of disabilities. In general, the guidelines do not include standard usability recommendations except where they have specific ramifications for accessibility beyond standard usability impacts.

Priorities and Techniques

This Working Draft of WCAG 2.0 builds upon WCAG 1.0 and reflects feedback received since the publication of WCAG 1.0 in May 1999. Although the same approaches to accessibility are followed in 1.0 and 2.0, the organization and structure have changed. Where WCAG 1.0 uses guidelines to group checkpoints, this Working Draft of WCAG 2.0 uses guidelines to group success criteria. Where WCAG 1.0 assigns a priority to a checkpoint , this Working Draft of WCAG 2.0 categorizes a success criterion into one of three levels.

In addition, the general design principles have been reworded to apply across a wide range of existing and emerging technologies. The WCAG 2.0 Working Draft does not include technology-specific implementation requirements or techniques, but it will link to technology-specific requirements as well as technology-specific examples and techniques (as soon as those documents are more stable).

The Web Content Accessibility Guidelines Working Group is working to ensure that organizations and individuals who are currently using WCAG 1.0 (which remains stable and referenceable at this time) will be able to smoothly transition to WCAG 2.0. For more information about the similarities and differences between WCAG 1.0 Checkpoints and WCAG 2.0 Guidelines and success criteria, please refer to the (draft) Mapping Between WCAG 1.0 and the WCAG 2.0 Working Draft .

Conformance

Editorial Note : There are several open issues with the proposed conformance scheme . This section outlines the conformance scheme used throughout this document. Feedback, comments, and proposals are encouraged.

Guidelines are divided into three categories of success criteria:

The Working Group believes that all success criteria should be testable. Tests can be done by computer programs or by people who understand these guidelines. Tests done by people who understand the guidelines should get the same results testing the same content for the same success criteria.

Editorial Note : To facilitate discussion related to the levels assigned to each criteria, a square bracket notation is included at the end of each criteria. "[I]" (invisible) indicates that a criterion does not specify how information is presented and "[V]" (visible) indicates that addressing the criterion may require an author to present content in particular ways.

Note:

Some guidelines do not contain level 1 success criteria.

Conformance Requirements

  1. Any conformance with WCAG 2.0 requires that all level 1 success criteria for all guidelines be met.

  2. WCAG 2.0 conformance at level A means that all level 1 success criteria for all guidelines are met.

  3. WCAG 2.0 conformance at level AA means that all level 1 and all level 2 success criteria for all guidelines are met.

  4. WCAG 2.0 conformance at level AAA means that all level 1, level 2 and level 3 success criteria for all guidelines are met.

Conformance Claims

All conformance claims must include at least the following information:

  1. The version of the guidelines to which the conformance claim is made.

  2. The URI of the authored unit for which the claim is being made.

    Editorial Note : There is question by some as to whether the term "authored unit" can be made precise enough.

    Editorial Note : There is some question as to whether URI is specific enough a reference to the material for which the claim is being made.

  3. The level of conformance being claimed.

Sites that conform to WCAG 1.0

Sites that currently conform to WCAG 1.0 that want to shift towards WCAG 2.0 will want to capitalize on past accessibility efforts. A qualified conformance statement could allow them this flexibility. For example, a conformance claim might include the following statement, "Materials created or modified before 24 April 2003 conform to WCAG 1.0. Materials created or modified on or after 24 April 2003 conform to WCAG 2.0."

Editorial Note : In some instances, the WCAG 2.0 Working Draft may be easier to conform to than the WCAG 1.0 Recommendation while other criteria might be harder to meet in WCAG 2.0 than in WCAG 1.0. The WCAG WG will consider the differences between WCAG 1.0 and WCAG 2.0 conformance and offer advice to developers who currently conform to WCAG 1.0. This advice might take the form of a WCAG 1.0 conformance profile to WCAG 2.0 and information about migrating from WCAG 1.0 to WCAG 2.0. This advice is not yet available.