(P) Time Delays
When a timed response is required, the user shall be alerted and given sufficient time to indicate more time is required.
Why do timed responses present problems to web users with disabilities?
Web pages can be designed with scripts so that the web page disappears or "expires" if a response is not received within a specified amount of time. Sometimes, this technique is used for security reasons or to reduce the demands on the computer serving the web pages. Someone's disability can have a direct impact on the speed with which he or she can read, move around, or fill in a web form. For instance, someone with extremely low vision may be a slower-than-average reader. A page may "time out" before he is able to finish reading it. Many forms, when they "time out" automatically, also delete whatever data has been entered. The result is that someone with a disability who is slow to enter data cannot complete the form. For this reason, when a timed response is required, the user shall be alerted via a prompt and given sufficient time to indicate whether additional time is needed.