Hi Sherzod,
Spasibo Brat!
I applied this code in an OnClick Event and added Form flag FShowMarkers because Series1.ShowMarkers is not updated in runtime. But hopefully this is solved in production.
...
FShowMarkers := not FShowMarkers;
JSInterface.JSCall('chart.getSeries()['+ IntToStr(SeriesList.IndexOf(Series1)) +'].setShowMarkers', [FShowMarkers]);
Appreciated,