WebPopupMenu.SelectionChanged
From Xojo Documentation
Event
The selected item has changed, either by user interaction with the control or via code. Use ListIndex to change the selection via code.
Notes
This is the equivalent of the desktop PopupMenu's Change event. It is past tense to reflect the fact that the change has already occurred when the event is called.
On Internet Explorer, this event is not called if you have implemented the MouseDown event. Consider using the MouseUp event instead.
Example
This code in the SelectionChanged event handler displays the selected item: