A free program for Chrome, by TPG Interactive.
With the ARC Toolkit, you can quickly and easily perform accessibility testing on any website. It's a handy tool that can be integrated into your development environment.
There are several different ways you can use the ARC Toolkit. You can add it as a rule in your webpages so it can automatically run when you visit them. You can also enable it to run manually, which means you can visit any page and it will run the tests for you.
You can also toggle it on and off so you can turn it on for a specific page and turn it off for another.
