Understanding SC 3.2.5: Change on Request (Level AAA)

In Brief

Goal

Users have full control of major content changes.

What to do

Provide ways for users to trigger or turn off changes of context.

Why it's important

Content that behaves predictably is especially important to people with disabilities.

Intent

The intent of this Success Criterion is to encourage design of Web content that gives users full control of changes of context. This Success Criterion aims to eliminate potential confusion that may be caused by unexpected changes of context such as automatic launching of new windows, automatic submission of forms after selecting an item from a list, etcetera. Such unexpected changes of context may cause difficulties for people with motor impairments, people with low vision, people who are blind, and people with certain cognitive limitations.

Some types of change of context are not disruptive to some users, or actively benefit some users. For example, single-switch users rely on context changes that are animated by the system, and the preferences of low-vision users may vary depending on how much of the content they can see at once and how much of the session structure they can retain in working memory. Some types of content, such as slide shows, require the ability to change context in order to provide the intended user experience. Content that initiates changes of context automatically only when user preferences allow can conform to this Success Criterion.

Benefits

• Individuals who are unable to detect changes of context or who may not realize that the context has changed are less likely to become disoriented if they initiate the change themselves. For example:

  • individuals who are blind or have low vision may have difficulty knowing when a visual context change has occurred, such as a new window popping up. 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 reading and intellectual disabilities, and who have difficulty interpreting visual cues may benefit from additional cues in order to detect changes of context.
• People with certain cognitive limitations do not get confused if automatic redirects are performed by the Web server instead of the browser.

Examples

an "update now" button

Instead of automatically updating the content, the author provides an "Update now" button that requests a refresh of the content.

An automatic redirection

Users are automatically redirected from an old page to a new page in such a way that they never realize the redirect has occurred.

Related Resources

Resources are for information purposes only, no endorsement implied.

• Use standard redirects: don't break the back button! (W3C QA Tip).
• HTTP/1.1 Status Code Definitions: Redirection 3xx.

Techniques

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this Success Criterion. A technique may go beyond the minimum requirement of the criterion. There may be other ways of meeting the criterion not covered by these techniques. For information on using other techniques, see Understanding Techniques for WCAG Success Criteria, particularly the "Other Techniques" section.

Test Rules

The following are Test Rules for certain aspects of this Success Criterion. It is not necessary to use these particular Test Rules to check for conformance with WCAG, but they are defined and approved test methods. For information on using Test Rules, see Understanding Test Rules for WCAG Success Criteria.

• Meta element has no refresh delay
• Meta element has no refresh delay (no exception)