W3C logoWeb Accessibility Initiative

WAI: Strategies, guidelines, resources to make the Web accessible to people with disabilities

Essential Components of Web Accessibility

Page Contents

This document shows how Web accessibility depends on several components working together and how improvements in specific components could substantially improve Web accessibility. It also shows how the WAI guidelines address these components.


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:

How the Components Relate

illustration showing how components relate, detailed description at http://www.w3.org/WAI/intro/components-desc.html#relate

Web developers usually use authoring tools and evaluation tools to create Web content.

People ("users") use Web browsers, media players, assistive technologies, or other "user agents" to get and interact with the content.

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:

The Implementation Cycle

When accessibility features are effectively implemented in one component, the other components are more likely to implement them.

illustration of implementation cycle, detailed description at http://www.w3.org/WAI/intro/components-desc.html#cycle

When One Component is Weak

If an accessibility feature is not implemented in one component, there is little motivation for the other components to implement it when it does not result in an accessible user experience. For example, developers are unlikely to implement an accessibility feature that authoring tools do not support and that most browsers or assistive technologies do not implement consistently.

illustration of what happens when one component is weak, detailed description at http://www.w3.org/WAI/intro/components-desc.html#weak

If one component has poor accessibility support, sometimes other components can compensate through "work-arounds" that require much more effort and are not good for accessibility overall. For example,

However, in most cases the works-arounds are not implemented and the result is still poor accessibility. Additionally, sometimes poor accessibility support in one component cannot be reasonably overcome by other components and the result is inaccessibility, making it impossible for some people with disabilities to use a particular Web site, page, or feature.

Guidelines for Different Components

The World Wide Web Consortium (W3C) Web Accessibility Initiative (WAI) develops Web accessibility guidelines for the different components:

WAI guidelines are based on the fundamental technical specifications of the Web, and are developed in coordination with:

illustration showing the guidelines for the different components, detailed description at http://www.w3.org/WAI/intro/components-desc.html#guide