var cellType = new GC.Spread.Sheets.CellTypes.Button(); 
cellType.buttonBackColor("#FFFF00"); 
cellType.text("this is a button"); 
activeSheet.setCellType(1,1,cellType);

spread.bind(GC.Spread.Sheets.Events.ButtonClicked, function (e, args) {
    var sheet = args.sheet, row = args.row, col = args.col;
    var cellType = activeSheet.getCellType(row, col);
    if (cellType instanceof GC.Spread.Sheets.CellTypes.Button) {
        alert("Button Clicked");
    }
});