var namedStyle = new GC.Spread.Sheets.Style();
namedStyle.name = "style1";
namedStyle.backColor = "green";
activeSheet.addNamedStyle(namedStyle);
activeSheet.setStyleName(1, 1, "style1"); // cell(1,1)'s backColor is  green.
activeSheet.setStyleName(2, 1, "style1");
alert(activeSheet.getStyleName(1,1,GC.Spread.Sheets.SheetArea.viewport));