Understanding Change in Content


This Success Criteria is intended to help users of assistive technology be aware of changes that many users can easily see and understand.

There are a number of cases where content changes on a page after it is loaded. Users who are blind or have low vision that rely on a screen reader may have trouble knowing that information on a page changed. They may be working on the part of the page which is not near where changes have occurred on a page. It may be on a part of the web page that they have already read and wouldn't consider reviewing that part of the page for unannounced changes.

These messages would be very short in nature, such as:

Examples of situations where this type of notification would be appropriate include:

Dynamic changes to a page sometimes cause the page to become inactive for a period of time while it is being updated. Users of assistive technology may think the page has crashed and may loose their work if they either reload the page or leave the page thinking the browser crashed. This notification will ensure they are aware that something is happening in the background, the way that sighted users are aware when they see a spinning icon or the words "loading". If there is no such visual indication there is no requirement in the Success Criterion to provide programmatic notification, only when there is a visual notification, is there a requirement to make that notification also programmatic. This is not about the initial wait to load a new page. Those are announced to screen readers.

Note: SC 4.1.2 covers notification of changes in content that are a result of a change in the state of a control, such as selecting a new Tab in a tabbed interface, opening and closing a menu, clicking a link or button that opens up a dialog or tooltip. The text of 4.1.2 is "... states, properties, and values that can be set by the user can be programmatically set; and notification of changes to these items is available to user agents, including assistive technologies."






This section references techniques that can be used to meet the Guideline or Success Criterion. There are sub-sections for sufficient techniques, advisory techniques, and failures.

Remove any parts of the template that are not used, such as the section and heading for situations, sub-lists of techniques, or the "AND" construction. Also remove the square brackets around placeholder optional components.


Techniques that are sufficient to meet the Guideline or Success Criterion.



Techniques that are not sufficient by themselves to meet the Guideline or Success Criterion.

Same template as sufficient techniques.


Techniques that document conditions that would cause the page not to meet the Guideline or Success Criterion, even if sufficient techniques are also used.

Same template as sufficient techniques.

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