Accessibility supported technologies
Use web content technologies in ways that are accessibility supported and work with the assistive technologies that people use.
Meeting the Web Accessibility Standard
When the following requirements are met, this satisfies WCAG Conformance Requirement 4:
- only accessibility supported ways of using web technologies are relied upon to ensure content meets WCAG success criteria
- any information or functionality that’s provided in a way that’s not accessibility supported is also available in a way that is accessibility supported.
The Web Content Accessibility Guidelines (WCAG) 2.1 form the basis of the New Zealand Government Web Accessibility Standard, and come with 5 conformance requirements.
For more about WCAG conformance, see Understanding Conformance — WCAG 2 — W3C.
What are web content technologies?
Web content technologies are things like the languages and different file formats that authors use to create web content that can be understood by user agents and presented to users.
The 3 core web content technologies are:
- Hypertext Markup Language (HTML): a markup language that’s used to structure web content
- Cascading Style Sheets (CSS): a style sheet language that’s used to describe how HTML elements are to be displayed on the screen
Other examples of web content technologies are:
- Portable Document Format (PDF), a document file format
- Graphics Interchange Format (GIF), an image format used to create animations
- MathML, a markup language used to represent mathematical and scientific expressions.
What is ‘accessibility support’?
Accessibility support is about making sure that web content is implemented in ways that work with the user agents, including assistive technologies (AT), that people use. It defines how web content technologies can be used to meet WCAG 2 Success Criteria.
For a detailed explanation, see Understanding Accessibility Support — WCAG 2 — W3C.
For more on how web content is consumed and presented by user agents and AT, see the Knowledge Area: Browsers, code and assistive technologies.
What does ‘accessibility supported’ mean?
‘Accessibility supported’ refers to a web content technology:
- that is used in a way that works with the AT and the accessibility features of browsers, operating systems, and other user agents that people use
- for which there are user agents and AT that people have access to and can use. This means that at least one of the following is true:
- The technology is supported in common user agents or plug-ins, such as browser add-ons or extensions, that work with the AT that people use.
- The technology is used in a closed environment, such as a government office, where the user agents available support the technology and work with the AT that people use.
- The technology is supported in one or more user agents that work with the AT that people use, and are as costly and as easy to procure for a disabled person as for a non-disabled person.
For further explanation, see What does accessibility supported mean? — TPGi.
Use accessibility supported technologies
When producing web content:
- Use web content technologies in ways that are supported by the browsers, AT and operating systems that your audience commonly uses.
- Use web content technologies according to their WCAG 2 Techniques for meeting specific WCAG 2 Success Criteria.
- Avoid using web content technologies in ways that replicate WCAG 2 Common Failures.
- If the content is implemented using web content technologies in ways that are not accessibility supported, provide an equivalent version of the content that uses technologies in accessibility supported ways and that can be accessed despite the non-accessibility-supported use of technologies.
What is or is not accessibility supported?
WCAG defines what constitutes accessibility support, but it does not specify which technologies can be considered accessibility supported in any given situation.
Determining if a particular use of web content technology is accessibility supported can be tricky. As noted in WCAG 2 Understanding Conformance,
[i]ndividual authors will not usually be able to do all of the testing necessary to determine which ways of using which Web technologies are actually supported by which versions of assistive technologies and user agents.
The amount of testing and documentation that’s needed to create and maintain a comprehensive repository of accessibility support information is even greater. Understandably, the breadth and currency of accessibility support information that’s available is often limited. Keep this in mind when reviewing test results from the following resources:
- Accessibility support — a11ysupport.io
- Assistive technology compatibility tests — PowerMapper
- HTML5 Accessibility — html5accessibility.com.
Browsers, AT and operating systems: Open versus closed environments
The audience for most New Zealand government websites is the general public.
With some websites, the audience might be a more specific subset of the general public, such as registered members of a special working group. Government organisations also have internal websites, such as intranets and document management systems, that only employees can access.
Where the site owner does not have control over the browsers, AT and operating systems being used by those visiting the site, it must be assumed that people will be using the site with all sorts of browsers, AT and operating systems. This means that the website will need to be developed using web content technologies in ways that are accessibility supported by a broad range of user agents.
Where the site owner does have control of the environment in which people will be using the website, such as an organisation’s intranet, the specific browsers, AT and operating systems available to users can be constrained. In this case, web content technologies only need to be accessibility supported by those specific browsers, AT and operating systems.
Use WCAG 2 Techniques
For full details, see Techniques for WCAG 2 — W3C.
Note: Not all Techniques for WCAG 2 provide accessibility support.
For example, the Techniques include ways of using PDF. In the context of New Zealand Government public facing websites, however, where the range of users’ browsers, AT and operating systems cannot be controlled, PDF is not considered accessibility supported technology, and cannot be relied on to deliver an accessible experience. See PDF and Word not accessibility supported.
Avoid Common Failures
The Techniques for WCAG 2 include Common Failures, which define ways of using web technologies that will result in a lack of conformance with particular WCAG 2 Success Criteria. Get familiar with these Common Failures and make sure not to replicate them.
For more, see Common Failures — Techniques for WCAG 2 — W3C.
PDF and Word not accessibility supported
PDF and Microsoft Word cannot be relied on as accessibility supported web content technologies. HTML remains the preferred format for accessible web content that meets the New Zealand Government Web Accessibility Standard. If content is published as a PDF or Word document, the same content must also be published in accessible HTML.
PDF and Word documents viewed on the web also do not rearrange the page into a single column so that users who zoom in can still see or access all of the content without having to scroll left and right. WCAG 2 Success Criterion 1.4.10 Reflow requires that content be viewable at an effective page width of 320px without requiring horizontal scrolling.
For best practices on creating PDF and Word documents, see the Web Content Type: PDF and Office documents (Word, Excel, PowerPoint) (coming soon).