Web Accessibility Overlays: Guidance and Best Practice

The University of Michigan does not support or recommend overlays for web accessibility.

Overlays are products that may be added to websites to provide accessibility options, but have known limitations and may negatively impact users with disabilities.

Overlays are not a good alternative to making U-M digital products, services, and content accessible, and may take away time and resources from our shared goal of creating an accessible, equitable digital ecosystem.

For support with digital accessibility, contact our accessibility team.
If you are considering using an overlay, or already using an overlay, please contact our accessibility team.

As overlay offerings change, and build on recent AI advancements, U-M accessibility staff will continue to test them, follow industry guidance, and update our U-M guidance accordingly.

About Overlays

Overlays are third-party products that can be added to websites which are designed to make those websites more accessible. They apply third-party source code (typically JavaScript) to make improvements to the front-end code of the website (Overlay Fact Sheet).

However, our testing and most industry research show that overlays do not fix all or many accessibility issues, and may introduce significant accessibility barriers to some users.

These products may also be known as “widgets,” “solutions,” “AI-supported add-ons,” or “plug-ins.” These products are often introduced to users as a button using a standard accessibility icon (e.g., wheelchair icon) that can be added to a website.

Overlays may be marketed as a simple, one-stop accessibility solution that can resolve all accessibility issues on your website. We understand the appeal of making a powerful impact on accessibility. However, overlays may not fix accessibility issues, and should be examined critically.

Overlay Limitations and Issues

  • Overlays duplicate accessibility settings and features that are already available
    • Features like zoom, high contrast, and more, can be adjusted in operating systems, browsers, or assistive technology
    • People who use these features may have their preferred settings interrupted or broken by overlays
  • Overlays can create accessibility issues
    • Some overlays prevent people from navigating by keyboard
    • Overlays can prevent people from using their assistive technology
    • Overlays may create inaccurate labels for elements on webpages, including form fields, providing incorrect information to people using your website
  • Overlays can have unpredictable results
    • JavaScript frameworks may change a page as people interact with it
    • Some overlays have features that do not work, cause pages to crash, or prevent content from displaying correctly
    • Overlays may not appear when people use ad-blocking settings
    • Overlays may raise significant privacy and security concerns, for example, detecting people’s usage of assistive technology without their consent.

Additional Resources