Alert
An alert is an element that displays a brief, important message in a way that attracts the user's attention without interrupting the user's task. Dynamically rendered alerts are automatically announced by most screen readers, and in some operating systems, they may trigger an alert sound. It is important to note that, at this time, screen readers do not inform users of alerts that are present on the page before page load completes.
— Alert Pattern, WAI ARIA Authoring Practices Guide (APG)
§ Notes
Missing.css uses the <div role=alert class=box>
element for alerts.
You can use colorways to provide some visual context to the alert, but be sure to also spell it out in writing.
Keyboard Interaction
Not applicable.
§ Example