“Accessibility overlays”, also known as “accessibility widgets” and by other names, are products that claim to make your web content accessible automatically. Overlays typically consist of a few lines of Javascript that are added to a webpage and run when the page loads. 

Despite their claims, overlays do not make your website more accessible. Instead, they work at the browser level to modify your content in ways that may run counter to your user’s needs or your intentions for the website. Website managers are advised to avoid the use of overlay products and instead provide sites and content that are built with accessibility in mind.

Some reasons not to use overlays:

• Overlays do not bring your site into compliance with the ADA. Instead, they offer a temporary "best guess" modification to your content and design.
• Overlays cannot reliably generate descriptive content like ALT text for web images, text for hyperlinks, or labels for form fields
• Overlays often duplicate accessibility features that already exist, like magnification, contrast, text-to-speech, and other features of browsers, operating systems, and screen readers and other assistive technology.
• Overlays can interfere with a user’s preferred assistive tech or choices in the moment.
• Overlays add a third-party script to your website, raising potential security concerns.

Further information and resources

• 6 Reasons to Avoid Using Web Accessibility Overlays (University of Minnesota)
• Overlay Guidance (University of Michigan)
• About Overlays (Harvard University)
• Accessibility overlays can make websites less accessible (University of Washington)

Please direct questions or comments to itaccessibility@uiowa.edu