Indicates whether assistive technologies will present all, or only parts of, the changed region based on the change notifications defined by the aria-relevant attribute.

Both accessibility APIs and the Document Object Model [dom] provide events to allow the assistive technologies to determine changed areas of the document.

When the content of a live region changes, user agents SHOULD examine the changed element and traverse the ancestors to find the first element with aria-atomic set, and apply the appropriate behavior for the cases below.

1. If none of the ancestors have explicitly set aria-atomic, the default is that aria-atomic is false, and assistive technologies will only present the changed node to the user.
2. If aria-atomic is explicitly set to false, assistive technologies will stop searching up the ancestor chain and present only the changed node to the user.
3. If aria-atomic is explicitly set to true, assistive technologies will present the entire contents of the element, including the author-defined live region label if one exists.

When aria-atomic is true, assistive technologies MAY choose to combine several changes and present the entire changed region at once.

HTML Example

Used in roles

• All elements of the base markup

Value

•  True/False
  • Value representing either true or false. The default value for this value type is False, unless otherwise specified.

• False (default)
• Assistive technologies will present only the changed node or nodes.
• True:
  • Assistive technologies will present the entire changed region as a whole, including the author-defined label if one exists.