WCAG 2.0 & 2.1

WCAG 2.0 & 2.1

Web Content Accessibility Guidelines (WCAG) is developed through the W3C process in cooperation with individuals and organizations around the world, with a goal of providing a single shared standard for web content accessibility that meets the needs of individuals, organizations, and governments internationally.

The WCAG documents explain how to make web content more accessible to people with disabilities. Web “content” generally refers to the information in a web page or web application, including:

• Natural information such as text, images, and sounds
• Code or markup that defines structure, presentation, etc.

Content that conforms to WCAG 2.1 also conforms to WCAG 2.0.

And content that conforms to WCAG 2.2 will also conform to 2.1 and 2.0. (This is often called “backwards compatible”.) A website that meets WCAG 2.1 or 2.2 should meet the requirements of policies that reference WCAG 2.0. To put it another way: If you want to meet both WCAG 2.0 and WCAG 2.1, you can use the 2.1 resources and you don’t need to bother looking at 2.0.

WCAG 2.0 and WCAG 2.1 are both existing standards. WCAG 2.1 does not deprecate or supersede WCAG 2.0. W3C encourages you to use the most recent version of WCAG when developing or updating content or accessibility policies.

Other guidelines

WCAG is part of a series of accessibility guidelines, including the Authoring Tool Accessibility Guidelines (ATAG) and the User Agent Accessibility Guidelines (UAAG). Essential Components of Web Accessibility explains the relationship between the different guidelines.

Essential Components of Web Accessibility

Summary

This page shows how web accessibility depends on several components working together, and how improvements in specific components could substantially improve web accessibility.

It provides the foundation for understanding the different accessibility standards developed by the W3C Web Accessibility Initiative (WAI).

Introduction

It is essential that several different components of web development and interaction work together in order for the web to be accessible to people with disabilities. These components include:

• Content - the information in a web page or web application, including:
• natural information such as text, images, and sounds
• Code or markup that defines structure, presentation, etc.
• Web browsers, media players, and other “user agents”
• Assistive technology, in some cases - screen readers, alternative keyboards, switches, scanning software, etc.
• Users’ knowledge, experiences, and in some cases, adaptive strategies using the web
• Developers - designers, coders, authors, etc., including developers with disabilities and users who contribute content
• Authoring tools - software that creates websites
• Evaluation tools - web accessibility evaluation tools, HTML validators, CSS validators, etc.

Interdependencies between Components

There are significant interdependencies between the components; that is, the components must work together in order for the web to be accessible. For example, for alternative text on images:

• technical specifications address alternative text (for example, HTML defines the alternative text attribute (alt) of the image element (img))
• WAI guidelines (WCAG, ATAG, UAAG described below) - define how to implement alternative text for accessibility in the different components
• developers provide the appropriate alternative text wording
• authoring tools enable, facilitate, and promote providing alternative text in a web page
• evaluation tools are used to help check that alternative text exists
• user agents provide human and machine interface to the alternative text
• assistive technologies provide human interface to the alternative text in various modalities
• users know how to get the alternative text from their user agent and/or assistive technology as needed