A message with important, and usually time-sensitive, information.

An alert role is a simple way of providing a message to the user. The alert role is used when the user interaction is not required but the message should be conveyed.  Alerts are specialized forms of the status role, which will be processed as an atomic live region.

For example, in a chat application, information of people coming online and going offline should be intimated to the user. This will be a simple yet important message which do not require any user interaction. In some chat applications, only an audio intimation will be provided when a buddy comes online or goes away. It do not provide any information on who has come online and who has gone away. In such cases, an alert message can be an alternate for sound intimation.

Role="alert" should be provided in the node containing the alert message. Focus is not required to be set for these kinds of alert messages.

Alerts are assertive live regions and will be processed as such by assistive technologies. Since alerts are not required to receive focus, content authors should not require users to close an alert. If the operating system allows, the user agent should fire a system alert event through the accessibility API when the alert is created. If an alert requires focus to close the alert, then content authors should use alertdialog instead.

Note: Elements with the role alert have an implicit aria-live value of assertive, and an implicit aria-atomic value of true.