Should I use an accessibility overlay script?

February 10, 2021

Hi Pecan! I really want to make my website more accessible, but I don’t have a lot of time or money to spend on it. Can I just add one of those scripts that promises to fix my issues for me?

Thanks for asking! We recommend that you do not use any third-party scripts to try to fix your site’s underlying accessibility issues. It might sound like a good solution, but as with many shortcuts, it’s too good to be true.

These scripts, often called “accessibility overlays,” try to detect and repair accessibility problems by scripting things like adding alt attributes. They might also add buttons to change the font size, or turn on a “screen reader accessibility mode.”

Unfortunately, the overlays can’t fix many issues, and they can even make things worse! Only a subset of problems can be detected automatically, and even so, many of those still require human judgment to evaluate. And we’ve seen some examples where the overlay controls themselves were inaccessible.

Relying on a script is a big risk. Some vendors provide free versions of their scripts, but in many cases they charge money. If you look closely at their terms and conditions, you will see that they don’t actually guarantee anything. You as the site owner are still fully responsible for your site’s accessibility. In recent lawsuits against sites using overlays, the overlays haven’t provided any cover. (We’ve collected some links at the end of this page with more information.)

The best way to improve your site’s accessibility is to build accessibility into your processes. Use the tools and resources provided by our team and other campus groups. Use a website platform that supports accessibility, and make sure your content editors know how to create accessible content. That way, you won’t have to spend so much time on retrofitting.

Web accessibility overlays are also not sufficient for websites to meet the UC accessibility policy

But can I add it and let it help, as I think some visitors might benefit from the features, such as reading the content out loud?

In our experience, most people needing that kind of assistance already have their own access technology to do that for them, and they find that overlays actually get in the way of the tool they’re using and are comfortable with.

Also, if someone is using the overlay to read your website, that doesn’t help them with all the other sites out there. Those sites might have no overlay, or they may be using a different overlay that doesn’t do things the same way.

What about the privacy of third-party overlays? 

Because these overlays potentially allow a third party (that we have no control over, either contractually or otherwise) to manipulate the user experience and potentially collect information about users and their activity on our sites, the campus Privacy Office recommends that we not use such services. Any tool that accesses user information on your site that you don’t control presents a potential privacy risk.

OK, I’m convinced, but it’s hard to convince the rest of my team when these overlays look quick and cheap.

There’s been a lot of discussion in the accessibility world about overlays. Here are some articles that go into more detail about the legal, accessibility, and user experience problems that they can create.