Understanding WCAG 2.0

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Understanding SC 2.2.4

2.2.4 Interruptions: Interruptions can be postponed or suppressed by the user, except interruptions involving an emergency. (Level AAA)

Intent of this Success Criterion

The intent of this Success Criterion is to allow users to turn off updates from the author/server except in emergencies. Emergencies would include civil emergency alert messages or any other messages that warn of danger to health, safety, or property, including data loss, loss of connection, etcetera.

This allows access by people with cognitive limitations or attention disorders by enabling them to focus on the content. It also allows users who are blind or have low vision to keep their "viewing" focus on the content they are currently reading.

Specific Benefits of Success Criterion 2.2.4:

  • Individuals with attention deficit disorders can focus on content without distraction.

  • Individuals with low vision or who use screen readers will not have content updated while they are viewing it (which can lead to discontinuity and misunderstanding if they start reading in one topic and finish in another).

Examples of Success Criterion 2.2.4

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Techniques and Failures for Success Criterion 2.2.4 - Interruptions

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. [begin change]However, it is not necessary to use these particular techniques. Any techniques, whether published by the WCAG group or not, can be sufficient if a) they satisfy the Success Criterion and b) all of the WCAG 2.0 conformance requirements have been met.[end change]

Additional Techniques (Advisory) for 2.2.4

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.

(none currently documented)

Common Failures for SC 2.2.4

The following are common mistakes that are considered failures of Success Criterion 2.2.4 by the WCAG Working Group.

Key Terms


a sudden, unexpected situation or occurrence that requires immediate action to preserve health, safety, or property