The nsIDOMMessageEvent interface is used for server-sent events and for
cross-domain messaging.
For more information on this interface, please see
http://www.whatwg.org/specs/web-apps/current-work/#messageevent
Initializes this event with the given data, in a manner analogous to
the similarly-named method on the nsIDOMEvent interface, also setting the
data, origin, source, and lastEventId attributes of this appropriately.
Custom string data associated with this event.
The origin of the site from which this event originated, which is the
scheme, “:”, and if the URI has a host, “//” followed by the
host, and if the port is not the default for the given scheme,
“:” followed by that port. This value does not have a trailing slash.
The last event ID string of the event source, for server-sent DOM events; this
value is the empty string for cross-origin messaging.
The window which originated this event.