Confirmation dialog box

Confirmation dialog (sometimes called warning alert boxes) is a dialog box that asks user to approve requested operation. Usually this dialog appears before a potentially dangerous operation is performed (program termination, file deletion, etc.)
Typically confirmation dialog boxes have two buttons (e.g. "Yes" / "No", "Confirm" / "Cancel") or three buttons (e. g. "Save" / "Discard" / "Cancel").
Some human interface guidelines recommend avoiding unnecessary confirmation dialogs. BlackBerry and Sun Java UI guidelines recommended a confirmation button be put before a cancellation button; but a default button should not be associated with a major destructive action.