Understanding Success Criterion 3.2.5: Change on Request

Success Criterion 3.2.5 Change on Request (Level AAA): Changes of context are initiated only by user request or a mechanism is available to turn off such changes.

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.

Note

It is possible for more than one change of context to occur simultaneously. For example, clicking on a link which automatically opens a new window is an example of two separate changes of context related to the change in content and to the change in the viewport (window). The change in the content in this case is initiated by user request when they click on the link, but unless the user can be aware that the link will open in a new window then that change of context cannot be regarded as user-initiated.

Benefits

Examples

Related Resources

Resources are for information purposes only, no endorsement implied.

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. However, it is not necessary to use these particular techniques. For information on using other techniques, see Understanding Techniques for WCAG Success Criteria, particularly the "Other Techniques" section.

Sufficient Techniques

Select the situation below that matches your content. Each situation includes techniques or combinations of techniques that are known and documented to be sufficient for that situation.

Situation A: If the Web page allows automatic updates:

  1. G76: Providing a mechanism to request an update of the content instead of updating automatically

Situation B: If automatic redirects are possible:

  1. SVR1: Implementing automatic redirects on the server side instead of on the client side
  2. G110: Using an instant client-side redirect using one of the following techniques:

Situation C: If the Web page uses pop-up windows:

  1. Including pop-up windows using one of the following techniques:

Situation D: If using an onchange event on a select element:

  1. SCR19: Using an onchange event on a select element without causing a change of context

Advisory Techniques

Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.

Failures

The following are common mistakes that are considered failures of this Success Criterion by the WCAG Working Group.

Key Terms

mechanism

process or technique for achieving a result

Note

The mechanism may be explicitly provided in the content, or may be relied upon to be provided by either the platform or by user agents, including assistive technologies.

Note

The mechanism needs to meet all success criteria for the conformance level claimed.