 var sheet1 = spread.getSheet(0),
  sheet2 = spread.getSheet(1);

sheet1.bind(GC.Spread.Sheets.Events.TopRowChanged, function (sender, args) {
    //Set the displayed top row of sheet1 to sheet2 (vertical scroll synchronization).
    sheet2.showRow(args.newTopRow, GC.Spread.Sheets.VerticalPosition.top);
});

sheet1.bind(GC.Spread.Sheets.Events.LeftColumnChanged, function (sender, args) {
    //Set the displayed left column of sheet1 to sheet2 (Horizontal scroll synchronization).
    sheet2.showColumn(args.newLeftCol, GC.Spread.Sheets.HorizontalPosition.left);
});