Using the aria-relevant attribute

The aria-relevant attribute is an optional value used to describe what types of changes have occurred to an aria-live region, and which are relevant and should be announced. Any change that is not relevant acts in the same manner it would if the aria-live attribute were set to off.

aria-relevant is commonly used when a web page contains content that may be updated while viewing the page.

Values

A space-delimited list of one or more of the following values:

additions
Additions of Element Nodes within the live region should be considered relevant.
removals
Deletion of Nodes from the live region should be considered relevant.
text
Changes to the textual content of existing nodes should be considered relevant.
all
Equivalent to additions removals text.

aria-relevant="additions text" is the default value on a live region.

Additional resources