Web Content Accessibility Guidelines

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Web Content Accessibility Guidelines (WCAG) are part of a series of web accessibility guidelines published by the World Wide Web Consortium (W3C), the main international standards organization for the Internet. These guidelines are designed to make web content more accessible to people with disabilities, including but not limited to blindness and low vision, deafness and hearing loss, limited movement, speech disabilities, photosensitivity, and combinations of these. Following WCAG is also often considered best practice for making web content more usable for all users.

Overview

The WCAG documents explain how to make web content more accessible to people with disabilities. Web content generally refers to the information in a web page or web application, including natural information such as text, images, and sounds, as well as code or markup that defines structure, presentation, etc.

The guidelines are part of the W3C's Web Accessibility Initiative (WAI), which works to make the Web accessible to all by developing guidelines, resources, and strategies. The WCAG are intended to be applicable to all web content, technologies, and be used in conjunction with other WAI guidelines on authoring tools and user agents.

Versions

There have been several versions of the WCAG, with each version seeking to address the evolving landscape of web technologies and the needs of users with disabilities.

WCAG 1.0

The first version, WCAG 1.0, was published in 1999 and consists of 14 guidelines. Each guideline has a series of checkpoints with a priority level assigned based on the impact on accessibility.

WCAG 2.0

WCAG 2.0, released in December 2008, introduced principles organized around four principles: perceivable, operable, understandable, and robust (POUR). It also introduced three levels of conformance: A (lowest), AA, and AAA (highest).

WCAG 2.1

WCAG 2.1, published in June 2018, extends WCAG 2.0 by adding more guidelines and success criteria aimed at improving accessibility for users with cognitive and learning disabilities, users with low vision, and users with disabilities on mobile devices.

WCAG 2.2

WCAG 2.2 is a draft version that aims to further improve accessibility guidelines based on feedback from WCAG 2.1 and evolving web technologies.

Principles

The core principles of WCAG, which are intended to be universal principles of accessible web design, are:

• Perceivable: Information and user interface components must be presentable to users in ways they can perceive.
• Operable: User interface components and navigation must be operable.
• Understandable: Information and the operation of the user interface must be understandable.
• Robust: Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies.

Applying WCAG

To meet the needs of different groups and different situations, WCAG 2.x includes three levels of conformance: Level A, Level AA, and Level AAA. Websites and web applications aim for at least Level AA conformance to ensure that they are accessible to people with a wide range of disabilities.

Importance

Adhering to WCAG is important not only for ethical reasons and to ensure equal access to information and services for all users but also for legal reasons. In many countries, web accessibility is a legal requirement for public and sometimes private websites.

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