ASU's IT Accessibility DOES NOT RECOMMEND the use of accessibility overlays. Overlays do not make websites fully accessible and complaint with WCAG and can sometimes lead to more accessibility problems.
What are overlays?
"Overlays are a broad term for technologies that aim to improve the accessibility of a website. They apply third-party source code (typically JavaScript) to make improvements to the front-end code of the website." (Overlay Fact Sheet)
What problems can overlays cause?
Overlays use Javascript to correct faulty HTML on the fly. The problems with this approach are:
- A high performance hit: Running the overlay script to change code on the fly can reduce page loading times to unacceptably slow levels.
- Many accessibility issues remain unfixed: These scripts are only able to detect and fix at the most 25-30% of accessibility issues. The remainder still require manual testing and/or manual corrections.
- False sense of security: Many people who purchase an overlay believe their site is fully complaint and that they don't have to do any other accessibility work. See #2 above. Over 900 web sites using accessibility widgets received lawsuits in 2023 (UsableNet).
- Additional accessibility issues: Overlays often interfere with our users assistive technology. For example, users who are blind have their preferred screen reader set up and configured to work with their browser in the way that's most helpful for them. Turning on an overlay forces that user to abandon their own screen reader and try to figure out and use an unfamiliar and less helpful substitute.
What to do instead?
Learn to create accessible sites, courses and content. It isn't difficult, although it may require you to learn a few new tricks and ways of thinking about your content.
Learn about accessibility based on your role at ASU. Or explore the many accessibility training options available to you.
Resources
A few of the organizations that have come out against overlays include:
You can find more information at:
