The Web Content Accessibility Guidelines (WCAG) are the internationally recognised guidelines for accessible web content.
They are published by the World Wide Web Consortium (W3C) and form the basis of many digital accessibility laws.
What are the WCAG?
WCAG describe how websites, apps and documents must be designed so that people with visual, hearing, motor or cognitive impairments can use them.
Version 2.1 was published in 2018 and version 2.2 in 2023.
Each version extends the previous one without replacing it.
International laws and guidelines for websites
In the EU, the standard EN 301 549, the Web Accessibility Directive for public bodies and the European Accessibility Act refer to WCAG.
In the USA, Canada and many other countries, WCAG also serve as the benchmark, for example for the ADA and Section 508.
Structure of the Web Content Accessibility Guidelines (WCAG)
WCAG are organised into principles, guidelines, success criteria and techniques.
This lets them serve both as a guiding idea and as a testable checklist.
Four Principles of Accessibility According to the Web Content Accessibility Guidelines
- Perceivable: content can be taken in through more than one sense, for example through text alternatives and captions.
- Operable: everything works with a keyboard and without time pressure.
- Understandable: text is clear, and operation and error messages are predictable.
- Robust: content works with browsers and assistive technology such as screen readers.
WCAG-Compliant CAPTCHAs for Best Web Accessibility
The success criterion on non-text content requires at least one alternative for other senses for CAPTCHAs.
Best of all is a method without any puzzle: CDPCaptcha checks through computational work in the background and needs neither sight nor hearing.
Success Criteria for WCAG Web Accessibility
Each guideline has testable success criteria at levels A, AA and AAA.
Laws usually require level AA, which includes all criteria of A and AA.
Techniques for WCAG Conformance and Web Accessibility
The W3C describes sufficient and advisory techniques as well as common failures.
They show developers exactly how to meet a criterion, for example with labels for form fields or ARIA attributes.
What Are WCAG Requirements for Web Accessibility?
- A contrast ratio of at least 4.5 to 1 for normal text
- Text alternatives for images and controls
- Full keyboard operation with a visible focus
- Labelled form fields and understandable error messages
- Zoom up to 200 percent without loss of content
Web Content Accessibility Guidelines as the Key to Digital Accessibility
Implementing WCAG covers the basis of most laws and makes an offer usable for everyone.
That applies to every page and every form, including spam protection.