Edition for Web Developers — Last Updated 16 January 2024
The WebSocket
interface used
to be defined here. It is now defined in WebSockets. [WEBSOCKETS]
MessageEvent
interfaceSupport in all current engines.
Messages in server-sent events, cross-document messaging,
channel messaging, broadcast channels, and WebSockets use
the MessageEvent
interface for their message
events: [WEBSOCKETS]
event.data
Returns the data of the message.
event.origin
Returns the origin of the message, for server-sent events and cross-document messaging.
event.lastEventId
Returns the last event ID string, for server-sent events.
event.source
Returns the WindowProxy
of the source window, for cross-document
messaging, and the MessagePort
being attached, in the connect
event fired at
SharedWorkerGlobalScope
objects.
event.ports
Returns the MessagePort
array sent with the message, for cross-document
messaging and channel messaging.
Various APIs (e.g., WebSocket
, EventSource
) use the
MessageEvent
interface for their message
event
without using the MessagePort
API.