Accessibility problems can occur if your Web page times-out while a user is completing a form. For security reasons or to reduce the demands on the server, you may be tempted to design pages with scripts so that they disappear or "expire" if a response is not received within a specified amount of time.
A person with a disability may not be able to read, move around, or fill in a Web form within the prescribed amount of time. For this reason, the Access Board included the following standard:
When a timed response is required, the user shall be alerted and given sufficient time to indicate more time is required.
This is actually a performance standard rather than a design standard because it does not reference a specified length of time for users to respond. To satisfy this requirement, the actions you should take are twofold: