A change of user agent, viewport, user interface controls, or focus; or complete change of content.
Editorial Note: we removed "user interface controls" from this definition based on standard form control show/hide behavior practice such as Gez's example.
The intent of this success criterion is avoid confusion that could be caused by certain specific changes in the user agent or the content which the user cannot infer from his own interaction with the content.
Further below is a description of who benefits from this success criterion.
For auto-refreshing content:
Editorial Note: Timeouts are covered by covered by Guideline 2.2 L1 SC1, but WCAG 1.0 Checkpoint 7.4 (auto-refreshing pages) also maps to Guideline 3.2 L3 SC2.
For automatic redirects:
For pop-up windows:
Editorial Note: These techniques have not been written yet.
Provide automatic redirects by …
If you cannot use server-side redirects, implement automatic redirects by …
If you cannot use server-side redirects, implement automatic redirects by …
Editorial Note: Meta redirect with a timeout is not allowed by this success criterion. However, at Level 1, it is covered by Guideline 2.2 L1 SC1.
onblur
event to change the context.Individuals who are unable to detect changes of context or may not realize that the context has changed are less likely to become disoriented while navigating a site. This applies to people in the following ways:
Individuals who are blind or have low vision may have difficulty knowing when a visual context change, such as a new window popping up, has occurred. In this case, warning users of context changes in advance minimizes confusion when the user discovers that the back button no longer behaves as expected.
Some individuals with low vision, with dyslexia and who have difficulty interpreting visual cues may benefit from additional cues in order to detect changes of context.
Changes of context that are not initiated by a user action can be very irritating for people without disabilities.
Editorial Note: The first two benefits were simply copied from WCAG 2.0. The last one is a mainstream benefit that should not be added to the guidelines.