Guidelines
Guidelines for making web content accessible to the widest possible audience.
Digital accessibility
To guarantee digital accessibility, the W3C (World Wide Web Consortium) has developed a set of guidelines for the accessibility of web content. These guidelines, described in the Web Content Accessibility Guidelines (WCAG), explain how to make web content accessible to the widest possible audience. The first version was published in 2008. In October 2012, WCAG 2.0 became a recognized ISO standard.
WCAG 2.1 guidelines were published by the W3C on June 5, 2018. WCAG 2.1 extends WCAG 2.0 with 17 new success criteria.
On September 7, 2018, WCAG 2.1 at level AA was included in the European standard EN 301 549. This means that the WCAG 2.1 guidelines have become leading for compliance with the new legislation.
Since December 23, 2018, these guidelines are mandatory for all government organizations. This includes Dutch governments (central government, provinces, municipalities and water boards) and institutions from the (semi-)public sector.
More about WCAG 2.1Web Content Accessibility Guidelines (WCAG)
The guidelines are based on 4 principles:
- Perceivable
- Operable
- Understandable
- Robust
The principles are divided into 13 guidelines. Each of these guidelines has verifiable requirements (or ‘success criteria’).
These verifiable requirements are divided into three conformance levels: A, AA and AAA. These levels are classified according to the impact they have on the design or visual presentation of the page. In total there are 78 success criteria.
By focusing on principles, not technology, the W3C emphasizes the need to keep thinking about the different ways people interact with web content. For example, people can:
- use a keyboard instead of a mouse;
- use reading software or a braille display to read content;
- change the default browser settings to make the content more readable.
Applying the guidelines
Use the four principles to make your website accessible: make it perceivable, operable and understandable for everyone, and robust for all devices.
Principle 1: Perceivable
To comply with WCAG 2.1 Principle 1: Perceivable, it must be ensured that people can experience and interact with the website (and elements on the website) using the senses available to them.
- Give text alternatives to non-textual content.
- Provide audio and video content with a transcript.
- Provide subtitles for video content.
- Make sure content is logically structured.
- Use semantic (meaningful) code
- Make sure that each function can be used when the default text size is doubled.
Principle 2: Operable
To comply with WCAG 2.1 Principle 2: Operable, it must be ensured that people can find and use content on the website regardless of how they use it. For example, with assistive technologies.
- Make sure everything works with a keyboard.
- Show the keyboard focus.
- Use descriptive titles for pages and windows.
- Use descriptive links so that it is clear where they lead.
- Do not use flashing content.
Principe 3: Understandable
To comply with WCAG 2.1 Principle 3: Understandable, ensure that people and software can understand the content and how the website works.
- Allow software to determine the language of the page.
- Make the text legible and understandable.
- Make sure all form fields have visible and meaningful labels.
- Make it easy to identify the form fields that where incorrectly filled in.
Principe 4: Robust
To comply with WCAG 2.1 Principle 4: Robust it must be ensured that the content can be reliably interpreted by a wide range of user agents (including legacy, current and expected browsers and the assistive technology).
- Make use of error-free code
- Ensure maximum compatibility with current and future browsers and other utilities.
- Make sure that the assistive technology understands what each function is for and what state it is in.
