An introduction to the Web Content Accessibility Guidelines (WCAG). 

The Web Content Accessibility Guidelines, commonly abbreviated to WCAG, are the guiding principles of web accessibility.

The WCAG were created to provide guidance for developers, designers, digital content authors, and web accessibility professionals. They clarify exactly how web elements should be designed, developed and maintained, to enable an accessible user experience for all users regardless of their abilities.

The history of WCAG

The WCAG are managed and updated by none other than the World Wide Web Consortium (W3C). If you don't know, the W3C are the international online community that develops key standards and initiatives to sustain the long-term growth of the Web.

On May 5th, 1999 the first version of the guidelines was released - WCAG 1.0. This version focused primarily on HTML and this was a breakthrough at the time. With the growth of the internet and new advancements in how the web was built this edition eventually became outdated. 

On December 11th, 2008 the W3C released WCAG 2.0 which was focussed on a more technology agnostic approach rather than purely HTML. The WCAG 2.0 guidelines introduced support for other digital media including PDFs, Text Documents, Presentations, eBooks, and native apps.

In Australia, the Federal Government endorsed WCAG 2.0 in 2010 and put in place a National Transition Strategy in place to ensure all Government websites adhered to the WCAG 2.0 guidelines Level A by 2012, and Level AA by 2015. This was a huge move in the Australian web world and heavily impacted how web design, development and accessibility in and beyond Australia.

In 2018, the most commonly known version of the WCAG guidelines were introduced - WCAG 2.1. With 10 years having passed since the introduction of WCAG 2.0, the W3C recognised that changes were needed to cover all of the new web advancements that had emerged. The WCAG 2.1 brought 16 additional requirements on top of the WCAG 2.0.

Fast forward to 2020 and the W3C have released a renewed version of the Web Content Accessibility Guidelines - WCAG 2.2. The most recent version builds upon and is backwards compatible with the WCAG 2.1 edition and only implements a one new success criterion that regulates keyboard focus areas - “2.4.11. Focus Visible”.

Below we’ve broken down the four foundational principles of accessibility that guide the WCAG 2.0, 2.1, and 2.2 requirements. For the most recent full set of criteria, please see the WCAG Guidelines here.


Guiding Principle 1: Perceivable

The first guiding principle of web accessibility and the WCAG is that information and user interface components must be “Perceivable”.

At its core, this principle means that the information on a web page can not be invisible to all of a user's senses. This principle seeks to tackle the issues created by the vast majority of websites that only provide content in audio or visual format. To be accessible, content needs to be available in multiple or alternative formats to accommodate for users of differing abilities.

For example, an embedded video needs to have a text transcript or closed captions so that users with auditory disabilities are able to perceive the information. Another example is the inclusion of alternative text descriptions for images and links which accurately describe the information or context conveyed by the visual content to users with screen readers.

Guiding Principle 2: Operable

The second guiding principle of the web accessibility standards is that components within a web page interface must be ‘Operable’ for all users. This principle aims to support users with mostly motor or physical disabilities. 

The largest requirement included due to this guiding principle is keyboard navigation. An accessible website must allow users to navigate it completely without the need for a mouse or anything but solely a keyboard. This requirement is met by websites with correct information structure and implementation of aria tags. 

Furthermore, any timing conditions on content must be flexible so that users are allowed sufficient time to understand and operate the content. All web elements should also avoid content that frequently changes or flashes that might negatively impact users with cognitive disabilities or disorders such as epilepsy.

Guiding Principle 3: Understandable

The 'Understandable' principle of the Web Content Accessibility Guidelines seeks to ensure a web page’s information and interface can easily be understood by users of all abilities. 

First and foremost, this principle ensures that the page language is correct and that content is communicated in a way that is not overcomplicated or difficult to understand. For example, a web page that utilised extremely unusual words or unexplained abbreviations would create barriers for users trying to understand the content.

Furthermore, a big component of a website's understandability is the predictability of the website content, information hierarchy and design structure. Another good example of how the WCAG guidelines ensure understandability is through assistance for any forms, fields or other elements that require a user's input. For example, if a user incorrectly enters their email address in an enquiry form, accurate and informational prompts should allow a user to easily understand the issue and rectify it.

Guiding Principle 4: Robust

The 'Robust' principle seeks to ensure that a web page and it’s content is robust enough to be accurately interpreted with any advancing technologies, such as multiple web browsers, assistive screen readers or voice activated devices. 

A website’s compatibility with a wide range of technologies is crucial to ensure no barriers are created for users in different technology situations. Depending on the device being used, users may only have access to one browser type (e.g. Internet Explorer, Google Chrome, Mozilla Firefox, Safari). Each of these browsers have slightly different builds and can replicate a website’s design or functionality slightly differently. Cross-browser compatibility is a large consideration for web developers when creating new platforms. 

Furthermore, assistive technologies are extremely useful for many user groups. For example, screen reader technology provides audio dictations of a website’s content so that users with visual impairments are able to fully understand and utilise them. In addition, speech recognition assistive technologies such as Dragon, support users with physical abilities in navigating web platforms using just their voice and a headset. 

Assistive technologies have been a major breakthrough in the web accessibility field over the past decade and have broken down many barriers for key disabled user groups.