1. Dart
2. dart:html
3. ShadowRoot
4. activeElement property

ShadowRoot class

1. Properties
2. activeElement
3. applyAuthorStyles
4. delegatesFocus
5. fullscreenElement
6. host
7. innerHtml
8. mode
9. olderShadowRoot
10. pointerLockElement
11. resetStyleInheritance
12. styleSheets
13. baseUri
14. childNodes
15. children
16. firstChild
17. hashCode
18. isConnected
19. lastChild
20. nextNode
21. nodeName
22. nodes
23. nodeType
24. nodeValue
25. on
26. ownerDocument
27. parent
28. parentNode
29. previousNode
30. runtimeType
31. text
32. Methods
33. elementFromPoint
34. elementsFromPoint
35. getSelection
36. addEventListener
37. append
38. appendHtml
39. appendText
40. clone
41. contains
42. dispatchEvent
43. getElementById
44. getRootNode
45. hasChildNodes
46. insertAllBefore
47. insertBefore
48. noSuchMethod
49. querySelector
50. querySelectorAll
51. remove
52. removeEventListener
53. replaceWith
54. setInnerHtml
55. toString
56. Operators
57. operator ==
58. Static properties
59. supported

Element get activeElement native;