Developed by the World Wide Web Consortium (W3C), whose members include Microsoft Corporation, Facebook, and Google, Inc., among others, the WCAG 2.0 guidelines provide a detailed standard for web content accessibility. Although highly technical and clearly written for web developers, counsel for entities with websites should be familiar with the guidelines and advise clients on their use. There are 12 guidelines organized into four principles: perceivable, operable, understandable, and robust. Each guideline has testable success criteria at three levels: A, AA, and AAA. The DOJ favors the AA Success Criteria. Following the guidelines will make websites more accessible to persons with disabilities who use assistive technologies such as speech-to-text software, scanning and switches, etc.
The user should be able to perceive the information and user interface components using their available senses. For example, developers should provide text alternatives for nontext content. This can mean providing captions for audio content and adding in audio descriptions of visual details in video. Sign language can also be added for audio content, including signed descriptions of sounds that are not speech. Developers should create content that can be presented in different ways, including by assistive technologies, without losing meaning.
Websites should have a site map with headings, lists, and tables that are marked-up properly. Designers can make it easier to see and hear content by separating background from foreground using sufficient contrasting colors and not relying on color as the only way of conveying information or identifying content. Text should be resizable up to 200 percent without losing information, and images of text should be resizable, replaced with actual text (i.e., using actual text instead of pictures of words), or avoided where possible.
The features of the website should be operable by either assistive technology or adaptive strategies. This means making all functionality available from the user’s keyboard so that anything the mouse can do, the keyboard can also do. This allows programs such as speech-to-text to simulate keyboard functions. In addition, keyboard functions, such as tabbing across options, should not get lost in the content. It should be clear where the user is on the page. If there is scrolling content, the user should be able to pause or stop the text, and if there is a timed session and it times out, the user should be able to log back in within a short period time without losing data or losing their place on the page.
To help avoid seizure in some epileptic users, avoid unnecessary flashing lights. Seizures triggered by flashing lights occur when the frequency flashing is between five and 30 flashes per second. Other factors can include brightness of the lights and contrast with background lighting. Avoid video content that may cause seizures.
Users should not only be able to understand the content, but also how to navigate the pages and the website as a whole. Developers should make the text readable and understandable. This means identifying within the code the primary language of a web page, such as English, Arabic, or Chinese. Use clear language and provide definitions of unusual words, phrases, or abbreviations. Further, content should appear and operate in predictable ways. Modes of navigating the pages and sites that repeat on multiple pages should be in the same place on each page. Features that appear on multiple pages should be labeled identically on each page.
Lastly, web pages should be designed to assist users in avoiding and correcting mistakes. Instructions and error messages should be clear and unambiguous. Error messages should also contain suggestions for correcting the error. Users should be given the opportunity to review and correct submissions, or even reverse submissions.
Content must be robust enough that it can be accessible by a wide variety of assistive technologies and adaptive strategies, even as assistive technologies improve. To do this, developers should maximize compatibility with current and future user tools by ensuring that page mark-ups can be reliably interpreted by assistive technologies and by providing name, role, and value for nonstandard page features.