Understanding Success Criterion 2.2.1: Timing Adjustable

For each time limit that is set by the content, at least one of the following is true:

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.

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.

Intent of Success Criterion 2.2.1: Timing Adjustable

The intent of this Success Criterion is to ensure that users with disabilities are given adequate time to interact with Web content whenever possible. People with disabilities such as blindness, low vision, dexterity impairments, and cognitive limitations may require more time to read content or to perform functions such as filling out on-line forms. If Web functions are time-dependent, it will be difficult for some users to perform the required action before a time limit occurs. This may render the service inaccessible to them. Designing functions that are not time-dependent will help people with disabilities succeed at completing these functions. Providing options to disable time limits, customize the length of time limits, or request more time before a time limit occurs helps those users who require more time than expected to successfully complete tasks. These options are listed in the order that will be most helpful for the user. Disabling time limits is better than customizing the length of time limits, which is better than requesting more time before a time limit occurs.

Any process that happens without user initiation after a set time or on a periodic basis is a time limit. This includes partial or full updates of content (for example, page refresh), changes to content, or the expiration of a window of opportunity for a user to react to a request for input.

It also includes content that is advancing or updating at a rate beyond the user's ability to read and/or understand it. In other words, animated, moving or scrolling content introduces a time limit on a users ability to read content.

In some cases, however, it is not possible to change the time limit (for example, for an auction or other real-time event) and exceptions are therefore provided for those cases.

Notes regarding server time limits

In cases where timing is not an intrinsic requirement but giving users control over timed events would invalidate the outcome, a third party can control the time limits for the user (for example, granting double time on a test).

See also .

Benefits of Success Criterion 2.2.1: Timing Adjustable

  • People with physical disabilities often need more time to react, to type and to complete activities. People with low vision need more time to locate things on screen and to read. People who are blind and using screen readers may need more time to understand screen layouts, to find information and to operate controls. People who have cognitive or language limitations need more time to read and to understand. People who are deaf and communicate in sign language may need more time to read information printed in text (which may be a second language for some).
  • In circumstances where a sign-language interpreter may be relating audio content to a user who is deaf, control over time limits is also important.
  • People with reading disabilities, cognitive limitations, and learning disabilities who may need more time to read or comprehend information can have additional time to read the information by pausing the content.

Examples of Success Criterion 2.2.1: Timing Adjustable

  • A Web site uses a client side time limit to help protect users who may step away from their computer. After a period of inactivity the Web page asks if the user needs more time. If it doesn't get a response – it times out.
  • A Web page has a field that automatically updates with the latest headlines in a rotating fashion. There is an interactive control that allows the user to extend the length of time between each update to as much as ten times the default. The control can be operated with either a mouse or a keyboard.
  • A Web page includes an animation which includes text that appears and disappears throughout. In some cases, the text is scrolling across the screen and in others, it is only displayed for a short time before it fades into the background. The page includes a pause button so that users who have trouble reading the text before it disappears can read it.
  • In an auction, there is a time limit on the amount of time a user has to submit a bid. Since the time limit applies to all users who want to bid on a particular item, it would be unfair to extend the time limit for any one particular user. Therefore, a time limit is required for this type of activity and no extension, adjustment, or deactivation of the time limit is required by this Success Criteria.
  • An on-line ticket-purchasing site gives the user two minutes to confirm a purchase before the seats are returned to the general pool. Because tickets on such sites can sell out quickly, holding a ticket longer than that may invalidate the nature of the site, so this is a case in which the timing is essential and cannot be extended without invalidating the activity. However, the site does move as much of the process out of the time-critical period as possible, for instance allowing users to provide necessary information like name, payment method, etc., before entering the time-critical stage.
  • A ticket-purchasing site allows the user two minutes to confirm purchase of selected seats, but warns the user when their time is almost out and allows the user to extend this time limit some number of times with a simple action such as clicking a "Extend time limit" button.

Resources Success Criterion 2.2.1: Timing Adjustable

Techniques for Success Criterion 2.2.1: Timing Adjustable

Sufficient Techniques

Situation A: If there are session time limits:

  1. Providing a checkbox on the first page of a multipart form that allows users to ask for longer session time limit or no session time limit
  2. Providing a way for the user to turn the time limit off

Situation B: If a time limit is controlled by a script on the page:

  1. Providing a way for the user to turn the time limit off
  2. Providing the user with a means to set the time limit to 10 times the default time limit
  3. Providing a script that warns the user a time limit is about to expire AND Allowing the user to extend the default time limit
  4. Providing a script that warns the user a time limit is about to expire and provides a way to extend it
  5. Allowing the user to extend the default time limit
  6. SL21

Situation C: If there are time limits on reading:

  1. G4: Allowing the content to be paused and restarted from where it was paused
  2. Providing a way for the user to turn the time limit off
  3. Using script to scroll content, and providing a mechanism to pause it
  4. Providing a mechanism to allow user to display moving, scrolling, or repeating text in a static window

Advisory Techniques

  • Using a script to poll the server and notify a user if a time limit is present (future link) (Scripting)
  • Using sounds to focus user's attention (future link)

Failures