🦽Accessability
Understanding Techniques for WCAG Success Criteria
Introduction to Web Accessibility | Web Accessibility Initiative (WAI) | W3C
Excerpt
The Website of the World Wide Web Consortium’s Web Accessibility Initiative.
Page Contents
Accessibility in Context
The power of the Web is in its universality. Access by everyone regardless of disability is an essential aspect.
The Web is fundamentally designed to work for all people, whatever their hardware, software, language, location, or ability. When the Web meets this goal, it is accessible to people with a diverse range of hearing, movement, sight, and cognitive ability.
Thus the impact of disability is radically changed on the Web because the Web removes barriers to communication and interaction that many people face in the physical world. However, when websites, applications, technologies, or tools are badly designed, they can create barriers that exclude people from using the Web.
Accessibility is essential for developers and organizations that want to create high-quality websites and web tools, and not exclude people from using their products and services.
What is Web Accessibility
Web accessibility means that websites, tools, and technologies are designed and developed so that people with disabilities can use them. More specifically, people can:
perceive, understand, navigate, and interact with the Web
contribute to the Web
Web accessibility encompasses all disabilities that affect access to the Web, including:
auditory
cognitive
neurological
physical
speech
visual
Web accessibility also benefits people without disabilities, for example:
people using mobile phones, smart watches, smart TVs, and other devices with small screens, different input modes, etc.
older people with changing abilities due to ageing
people with “temporary disabilities” such as a broken arm or lost glasses
people with “situational limitations” such as in bright sunlight or in an environment where they cannot listen to audio
people using a slow Internet connection, or who have limited or expensive bandwidth
For a 7-minute video with examples of how accessibility is essential for people with disabilities and useful for everyone in a variety of situations, see: Web Accessibility Perspectives Video (YouTube)
Accessibility is Important for Individuals, Businesses, Society
The Web is an increasingly important resource in many aspects of life: education, employment, government, commerce, health care, recreation, and more. It is essential that the Web be accessible in order to provide equal access and equal opportunity to people with diverse abilities. Access to information and communications technologies, including the Web, is defined as a basic human right in the United Nations Convention on the Rights of Persons with Disabilities (UN CRPD).
The Web offers the possibility of unprecedented access to information and interaction for many people with disabilities. That is, the accessibility barriers to print, audio, and visual media can be much more easily overcome through web technologies.
Accessibility supports social inclusion for people with disabilities as well as others, such as:
older people
people in rural areas
people in developing countries
There is also a strong business case for accessibility. As shown in the previous section, accessible design improves overall user experience and satisfaction, especially in a variety of situations, across different devices, and for older users. Accessibility can enhance your brand, drive innovation, and extend your market reach.
Web accessibility is required by law in many situations.
Making the Web Accessible
Web accessibility depends on several components working together, including web technologies, web browsers and other "user agents", authoring tools, and websites.
The W3C Web Accessibility Initiative (WAI) develops technical specifications, guidelines, techniques, and supporting resources that describe accessibility solutions. These are considered international standards for web accessibility; for example, WCAG 2.0 is also an ISO standard: ISO/IEC 40500.
Making Your Website Accessible
Many aspects of accessibility are fairly easy to understand and implement. Some accessibility solutions are more complex and take more knowledge to implement.
It is most efficient and effective to incorporate accessibility from the very beginning of projects, so you don’t need go back and to re-do work.
Evaluating Accessibility
When developing or redesigning a website, evaluate accessibility early and throughout the development process to identify accessibility problems early, when it is easier to address them. Simple steps, such as changing settings in a browser, can help you evaluate some aspects of accessibility. Comprehensive evaluation to determine if a website meets all accessibility guidelines takes more effort.
There are evaluation tools that help with evaluation. However, no tool alone can determine if a site meets accessibility guidelines. Knowledgeable human evaluation is required to determine if a site is accessible.
Examples
Alternative Text for Images
Images should include equivalent alternative text (alt text) in the markup/code.
If alt text isn’t provided for images, the image information is inaccessible, for example, to people who cannot see and use a screen reader that reads aloud the information on a page, including the alt text for the visual image.
When equivalent alt text is provided, the information is available to people who are blind, as well as to people who turn off images (for example, in areas with expensive or low bandwidth). It’s also available to technologies that cannot see images, such as search engines.
Keyboard Input
Some people cannot use a mouse, including many older users with limited fine motor control. An accessible website does not rely on the mouse; it makes all functionality available from a keyboard. Then people with disabilities can use assistive technologies that mimic the keyboard, such as speech input.
Transcripts for Audio
Just as images aren’t available to people who can’t see, audio files aren’t available to people who can’t hear. Providing a text transcript makes the audio information accessible to people who are deaf or hard of hearing, as well as to search engines and other technologies that can’t hear.
It’s easy and relatively inexpensive for websites to provide transcripts. There are also transcription services that create text transcripts in HTML format.
For More Information
W3C WAI provides a wide range of resources on different aspects of web accessibility standards, education, testing/evaluation, project management, and policy. We encourage you to explore this website, or look through the WAI Resources list.
Excerpt
WCAG 2.1 guidelines and success criteria are designed to be broadly applicable to current and future web technologies, including dynamic applications, mobile, digital television, etc. They are stable and do not change.
WCAG 2.1 guidelines and success criteria are designed to be broadly applicable to current and future web technologies, including dynamic applications, mobile, digital television, etc. They are stable and do not change.
Specific guidance for authors and evaluators on meeting the WCAG success criteria is provided in techniques, which include code examples, resources, and tests. W3C's Techniques for WCAG 2.1 document is updated periodically, about twice per year, to cover more current best practices and changes in technologies and tools.
The three types of guidance in Techniques for WCAG 2.1 are explained below:
Sufficient techniques
Advisory techniques
Failures
Also explained below:
General and technology-specific techniques - which can be sufficient or advisory
Other techniques - beyond what is in W3C's published document
Technique tests
User agent and assistive technology support
Using the techniques - with important considerations
Understanding Conformance provides related information, including on understanding accessibility support.
Techniques are Informative
Techniques are informative—that means they are not required. The basis for determining conformance to WCAG 2.1 is the success criteria from the WCAG 2.1 standard—not the techniques.
Note 1: W3C cautions against requiring W3C's sufficient techniques. The only thing that should be required is meeting the WCAG 2.1 success criteria. To learn more, see:
Note 2: Techniques for WCAG 2.1 uses the words "must" and "should" only to clarify guidance within the techniques, not to convey requirements for WCAG.
Sufficient Techniques
Sufficient techniques are reliable ways to meet the success criteria.
From an author's perspective: If you use the sufficient techniques for a given criterion correctly and it is accessibility-supported for your users, you can be confident that you met the success criterion.
From an evaluator's perspective: If web content implements the sufficient techniques for a given criterion correctly and it is accessibility-supported for the content's users, it conforms to that success criterion. (The converse is not true; if content does not implement these sufficient techniques, it does not necessarily fail the success criteria, as explained in Testing Techniques below.)
There may be other ways to meet success criteria besides the sufficient techniques in W3C's Techniques for WCAG 2.1 document, as explained in Other Techniques below. (See also Techniques are Informative above.)
Numbered Lists, "AND"
The W3C-documented sufficient techniques are provided in a numbered list where each list item provides a technique or combination of techniques that can be used to meet the success criterion. Where there are multiple techniques on a numbered list item connected by "AND" then all of the techniques must be used to be sufficient. For example, Sufficient Techniques for 1.3.1 has: "G115: Using semantic elements to mark up structure AND H49: Using semantic markup to mark emphasized or special text (HTML)".
Advisory Techniques
Advisory techniques are suggested ways to improve accessibility. They are often very helpful to some users, and may be the only way that some users can access some types of content.
Advisory techniques are not designated as sufficient techniques for various reasons such as:
they may not be sufficient to meet the full requirements of the success criteria;
they may be based on technology that is not yet stable;
they may not be accessibility supported in many cases (for example, assistive technologies do not work with them yet);
they may not be testable;
in some circumstances they may not be applicable or practical, and may even decrease accessibility for some users while increasing it for others;
they may not address the success criterion itself, and instead provide related accessibility benefits.
Authors are encouraged to apply all of the techniques where appropriate to best address the widest range of users' needs.
Failures
Failures are things that cause accessibility barriers and fail specific success criteria. The documented failures are useful for:
Authors to know what to avoid,
Evaluators to use for checking if content does not meet WCAG success criteria.
Content that has a failure does not meet WCAG success criteria, unless an alternate version is provided without the failure.
If anyone identifies a situation where a documented failure is not correct, please report the situation as a WCAG comment so that it can be corrected or deleted as appropriate.
General and Technology-specific Techniques
General techniques describe basic practices that apply to all technologies. Technology-specific techniques apply to a specific technology.
Some success criteria do not have technology-specific techniques and are covered only with general techniques. Therefore, both the general techniques and the relevant technology-specific techniques should be considered.
Publication of techniques for a specific technology does not imply that the technology can be used in all situations to create content that meets WCAG 2.1 success criteria and conformance requirements. Developers need to be aware of the limitations of specific technologies and provide content in a way that is accessible to people with disabilities.
Other Techniques
In addition to the techniques in W3C's Techniques for WCAG 2.1 document, there are other ways to meet WCAG success criteria. W3C's techniques are not comprehensive and may not cover newer technologies and situations.
Web content does not have to use W3C's published techniques in order to conform to WCAG 2.1.__(See also Techniques are Informative above.)
Content authors can develop different techniques. For example, an author could develop a technique for HTML5, WAI-ARIA, or other new technology. Other organizations may develop sets of techniques to meet WCAG 2.1 success criteria.
Any techniques can be sufficient if:
they satisfy the success criterion, and
all of the WCAG 2.1 conformance requirements are met.
Submitting Techniques
The WCAG Working Group encourages people to submit new techniques so that they can be considered for inclusion in updates of the Techniques for WCAG 2.1 document. Please submit techniques for consideration using the Techniques Submission Form.
Testing Techniques
Each technique has tests that help:
authors verify that they implemented the technique properly, and
evaluators determine if web content meets the technique.
The tests are only for a technique, they are not tests for conformance to WCAG success criteria.
Failing a technique test does not necessarily mean failing WCAG, because the techniques are discrete (that is, they address one specific point) and they are not required.
Content can meet WCAG success criteria in different ways other than W3C's published sufficient techniques.
Content that passes the sufficient techniques for a specific technology does not necessarily meet all WCAG success criteria. Some success criteria have only general techniques, not technology-specific techniques.
The content must be accessibility supported for the content's users. Some sufficient techniques require browser, assistive technology, or other support that some users might not have.
Thus while the techniques are useful for evaluating content, evaluations must go beyond just checking the sufficient technique tests in order to evaluate how content conforms to WCAG success criteria.
Failures are particularly useful for evaluations because they do indicate non-conformance (unless an alternate version is provided without the failure).
User Agent and Assistive Technology Support Notes
Some techniques require that web content users have specific browsers or assistive technologies in order for the technique to be accessibility-supported. The User Agent and Assistive Technology Support Notes sections of individual techniques include some information to help determine accessibility support.
Support Notes Change Over Time
As time passes, the versions of user agents (browsers, etc.) or assistive technologies listed may not be the current versions. The Working Group may not update most of these notes as new versions are released. Authors should test techniques with the user agents and assistive technologies currently available to their users. See also Understanding Accessibility Support.
Using the Techniques
Techniques for WCAG 2.1 is not intended to be used as a stand-alone document. Instead, it is expected that content authors will usually use How to Meet WCAG 2.1: A customizable quick reference to read the WCAG success criteria, and follow links from there to specific topics in Understanding WCAG 2.1 and to specific techniques.
Alternatives must meet success criteria
Some techniques describe how to provide alternate ways for users to get content. For example, G73: Providing a long description in another location with a link to it that is immediately adjacent to the non-text content mentions a transcript as an alternative for an audio file. Some alternatives must also conform to WCAG. For example, the transcript itself must meet all relevant success criteria.
Example Code
The code examples in the techniques are intended to demonstrate only the specific point discussed in the technique. They might not demonstrate best practice for other aspects of accessibility, usability, or coding not related to the technique. They are not intended to be copied and used as the basis for developing web content.
Many techniques point to "working examples" that are more robust and may be appropriate for copying and integrating into web content.
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