The Web Content Accessibility Guidelines 2.1 (WCAG 2.1) are a set of standards defined by the World Wide Web Consortium (W3C) that define how to make web content more accessible to people with disabilities. WCAG 2.1 defines four principles which provides the foundation for web accessibility:
- Perceivable – Information and user interface components must be presented to users in ways that they can perceive, regardless of the user’s functional impairment.
- Operable – User interface components and navigation must be operable, regardless of the assistive technology used to interact with the interface.
- Understandable – Information and the operation of the user interface must be predictable and understandable to the user.
- Robust – Content must be robust enough to be able to be transformed and interpreted by a wide variety of user agents, like assistive technologies.
The success criteria have three different conformance levels – A, AA, and AAA – with AAA being the most accessible. Additionally, there are “Sufficient and Advisory Techniques” that demonstrate coding techniques.
Additional references are below: