This property defines the action to be invoked when an alarm is triggered.
IANA and non-standard property parameters can be specified on this property.
This property MUST be specified once in a "VALARM" calendar component.
Each "VALARM" calendar component has a particular type of action with which it is associated. This property specifies the type of action. Applications MUST ignore alarms with x-name and iana-token values they don't recognize.
This property is defined by the following notation:
action = "ACTION" actionparam ":" actionvalue CRLF
actionparam = *(";" other-param)
actionvalue = "AUDIO" / "DISPLAY" / "EMAIL" / iana-token / x-name
The following are examples of this property in a "VALARM" calendar component: