In a live region of the page where new content is added and the added content is intimated to the user the log (role) is used. Usually in applications such as chat widgets the new message that arrives should be intimated to the user. This should follow a sequential order.
Elements with the role log have an implicit aria-live value of polite. However if the updated content should be intimated to the user interrupting the existing work aria-live can be set to assertive. When entire live region should be intimated to the user set aria-atomic=â€trueâ€.