Static factory designed to expose beforeunload
events to event handlers that are not necessarily instances of Window.
See EventStreamProvider for usage information.
static const EventStreamProvider<BeforeUnloadEvent> beforeUnloadEvent = const _BeforeUnloadEventStreamProvider('beforeunload')
© 2012 the Dart project authors
Licensed under the Creative Commons Attribution-ShareAlike License v4.0.
https://api.dartlang.org/stable/2.0.0/dart-html/Window/beforeUnloadEvent-constant.html