Implementing Rule P
§ 1194.22 Web-based intranet and internet information and applications.
(p) When a timed response is required, the user shall be alerted and given sufficient time to indicate more time is required.
- What Is a "Timed Response"?
- What Types of Items Have Timed Responses?
- How Should the User Be Alerted?
- What Is "Sufficient Time"?
- How Should the User Indicate More Time Is Needed?
What Is a "Timed Response"?
Loosely speaking, a "timed response" is a response by the user to an action initiated by the computer that needs to occur within a specific time. If the response occurs after that time, the user might no longer be able to continue to work on the page she is on.
Because some forms of assistive technology are slower in navigating Web pages than the common visual browsers, users of such technology need more time to respond to even ordinary events.
What Types of Items Have Timed Responses?
Session Variables
Some session variables are designed to expire after a period of time. If they expire before the user has finished her task, then she may be cut off and be unable to complete the task.
Tests/Forms
Some on-line forms or on-line tests may be programmed to time-out after a certain amount of time. If the test is necessarily time-limited, then an exemption needs to be granted for people with disabilities requiring more time. This exemption needs to be selected before the on-line process begins. Again, that depends on the nature of the test. If the nature of the test is to test how fast a user using a standard browser can fill out the form, then this exemption doesn't apply.
Otherwise, just remind the user that the session is about to time out, and allow enough time [!] to respond to that alert to extend the time for the larger process.
Moving Text
Because the text moves a specific distance across the screen over a specific time period, a method needs to be provided to allow the user to control the speed of the moves. Otherwise, the information will disappear before the user can access it. While repeating the message ad infinitum appears to solve the problem, such as in the use of a marquee, the user needs to be able to orient herself to the message again and pick up where she left off, something which might be difficult with certain message speeds. It would also require her to re-read parts of the message multiple times.
Scrolling text should either have a control to control the speed of the display of the text, or have an alternate text equivalent.
The best thing to do for marquee-like text is to emphasize (<em>)
or strongly state (<strong>) the message in a non-moving format.
The speed of all other moving text should be capable of being controlled by the user.
The <marquee> tag is not standard HTML,
and shouldn't be used.
Audio Presentations
Audio presentations, particularly of speech, need to be controlled by the user. Different people can absorb speech spoken at different rates; some have a hard time when the speaker speaks fast. The capability of controlling the rate of speech is a necessary feature to include, as well as playback.
Video Presentations
Whether automated slide shows, or movies, again, information is absorbed at different rates by different people. The capability of controlling the speed of the presentation is necessary, as well as the capability of playing it back.
This even includes synchronized captions, which are moving text.
Page Redirects
Page redirects are implemented in several ways:
- using a
<meta>tag - using a JavaScript
- using a static page
- at the domain level - several domains point to the same location
If the redirect information needs to be read by the user, then an automatic redirect will not be compliant. There is no legally-defined time period that can be programmed to allow the information to display, then vanish. The determination of whether the information has satisfactorialy been read is made by the user. Therefore, the two possible implementations of redirects that will be compliant are to use a static page, and allow the user to select the link to the new location, or to use a redirect tied into the domain name.
How Should the User Be Alerted?
What Is "Sufficient Time"?
How Should the User Indicate More Time Is Required?
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