2.2.1 - Timing adjustable
If there is any time limit (like a session timeout), give people an easy way to extend it.
Summary
When a time limit is set (like a session timeout), it must be possible for the user to turn it off, delay it, or extend the length of time.
Requirements
- If it is necessary to implement timeouts (e.g. for security reasons), users should be informed when a timeout is about to occur and be given the option to extend it.
Common mistakes
- A time limit is set, but a user is unable to turn it off, delay it, or extend it;
- A time limit warning is displayed, but a user’s attention is not drawn to it in an appropriate way.
Why?
This ensures that people who need longer to complete tasks because of cognitive or mobility impairments, are able to do so comfortably.
Official wording in the Web Content Accessibility Guidelines
2.2.1 Timing Adjustable: For each time limit that is set by the content, at least one of the following is true: (Level A)
- Turn off: The user is allowed to turn off the time limit before encountering it; or
- Adjust: The user is allowed to adjust the time limit before encountering it over a wide range that is at least ten times the length of the default setting; or
- Extend: The user is warned before time expires and given at least 20 seconds to extend the time limit with a simple action (for example, "press the space bar"), and the user is allowed to extend the time limit at least ten times; or
- Real-time Exception: The time limit is a required part of a real-time event (for example, an auction), and no alternative to the time limit is possible; or
- Essential Exception: The time limit is essential and extending it would invalidate the activity; or
- 20 Hour Exception: The time limit is longer than 20 hours.
Note: This success criterion helps ensure that users can complete tasks without unexpected changes in content or context that are a result of a time limit. This success criterion should be considered in conjunction with Success Criterion 3.2.1, which puts limits on changes of content or context as a result of user action.
See the W3C's detailed explanation of this guideline with techniques and examples.