1. Dart
2. dart:html
3. WindowEventHandlers
4. onlineEvent constant

WindowEventHandlers class

1. Properties
2. onHashChange
3. onMessage
4. onOffline
5. onOnline
6. onPopState
7. onStorage
8. onUnload
9. hashCode
10. on
11. runtimeType
12. Methods
13. addEventListener
14. dispatchEvent
15. noSuchMethod
16. removeEventListener
17. toString
18. Operators
19. operator ==
20. Constants
21. hashChangeEvent
22. messageEvent
23. offlineEvent
24. onlineEvent
25. popStateEvent
26. storageEvent
27. unloadEvent

static const EventStreamProvider<Event> onlineEvent =
    const EventStreamProvider<Event>('online')