1. Dart
2. dart:html
3. MessageEvent
4. data property

MessageEvent class

1. Constructors
2. MessageEvent
3. Properties
4. data
5. lastEventId
6. origin
7. ports
8. source
9. suborigin
10. bubbles
11. cancelable
12. composed
13. currentTarget
14. defaultPrevented
15. eventPhase
16. hashCode
17. isTrusted
18. matchingTarget
19. path
20. runtimeType
21. target
22. timeStamp
23. type
24. Methods
25. composedPath
26. noSuchMethod
27. preventDefault
28. stopImmediatePropagation
29. stopPropagation
30. toString
31. Operators
32. operator ==

dynamic get data => convertNativeToDart_SerializedScriptValue(this._get_data);