Web Accessibility Fundamentals

What is Web Accessibility and Why Does It Matter?

Web accessibility means that websites, tools, and technologies are designed and developed in a way so that people with disabilities can both use them and contribute to the Web.

The web was designed to work for all people regardless of their hardware, software, language, location, or ability. When software is correctly written for the Web, it removes the barriers to communication and interaction that many people face in the physical world. Tim Berners-Lee, the inventor of the World Wide Web is quoted as saying "The power of the Web is in its universality. Access by everyone regardless of disability is an essential aspect."

However, as web sites and applications have grown in complexity, design and code practices have taken hold that create barriers for disabled people on the Web. This is an unacceptable phenomena because our digital infrastructure on the Web is just as important as our physical infrastructure for completing our everyday tasks.

Web Accessibility's importance goes beyond altruism. It is important to remember that all of us are just an accident or a few years of age away from needing to use assistive technology, so it is in all of our best interest to strive towards creating an inclusive infrastructure for our ever increasingly digital lives.

Types of Disabilities

Web Accessibility encompasses all disabilities that affect access to the Web, including:

  • Motor: Partial or total loss of the function of a body part.
  • Visual: Partial or total loss of vision.
  • Auditory: Partial or total loss of hearing.
  • Cognitive: One who has a greater difficulty with one or more types of mental tasks than the average person.
  • Neurological: One who experiences seizures or vestibular issues when exposed to certain images and animations.
  • Situational: Certain situations where one becomes temporarily disabled. Examples include parents holding a new born while trying to operate a computer, reading text on a phone in direct sunlight, and watching Netflix in class or during a meeting.

How Web Accessibility is Evaluated

Each country has different accessibility requirements for companies, and government organizations, however, many have adopted a the same criteria that the W3C (the international consortium behind all the web's standards) has created. This standard is called the WCAG.


WCAG stands for the Web Content Accessibility Guidelines and is a document that explains how to make web content more accessible for people with disabilities. There are 3 levels of conformance within the WCAG: A, AA, AAA.

Single A criteria is the bare minimum needed for a disabled user to be able to use a website while AAA conformance also encompasses all A, AA, and AAA criteria and is the most inclusive standard to strive for. However, in many cases, AAA conformance is impractical or impossible to reach. Therefore, most governments and organization strive to conform to the WCAG AA standard.

Since the WCAG is a technical standard and not an introduction of accessibility, it can be somewhat terse and difficult to understand. However, it's core concepts boil down to making web content P.O.U.R..


P.O.U.R. stands for Perceivable, Operable, Understandable, and Robust.

Perceivable: Users are able to perceive the content through their senses via the browser or other assistive technology.

Operable:  Users can interact with all controls and interactive elements using either the mouse, keyboard, or an assistive device.

Understandable: Content is clear and limits confusion and ambiguity.

Robust: A wide range of technologies and devices can access the content.


Web accessibility is critical for building an equitable digital infrastructure. The Web was originally designed to work for all people and it is the responsibility of developers, designers, and testers that this remains true. The WCAG is the international standard that most governments and organization use to assess web accessibility. The main idea behind the WCAG is that the site is P.O.U.R. Perceivable, Operable, Understandable, and Robust.

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