The nonstandard way to access the element that the mouse comes
from in the case of a mouseover event.
This member is deprecated and not cross-browser compatible; use relatedTarget to get the same information in the standard way.
Source
@DomName('MouseEvent.fromElement')
@DocsEditable()
@deprecated
Node get fromElement =>
_blink.BlinkMouseEvent.instance.fromElement_Getter_(this);