var sheet1 = spread.getSheet(0);
sheet1.setRowCount(3);
sheet1.setColumnCount(5);
sheet1.options.colHeaderAutoText = GC.Spread.Sheets.HeaderAutoText.blank;
sheet1.options.rowHeaderAutoText = GC.Spread.Sheets.HeaderAutoText.blank;
sheet1.setText(0, 0, "Row1", GC.Spread.Sheets.SheetArea.rowHeader);
sheet1.setText(1, 0, "Row2", GC.Spread.Sheets.SheetArea.rowHeader);
sheet1.setText(2, 0, "Row3", GC.Spread.Sheets.SheetArea.rowHeader);
sheet1.setText(0, 0, "Column1", GC.Spread.Sheets.SheetArea.colHeader);
sheet1.setText(0, 1, "Column2", GC.Spread.Sheets.SheetArea.colHeader);
sheet1.setText(0, 2, "Column3", GC.Spread.Sheets.SheetArea.colHeader);
sheet1.setText(0, 3, "Column4", GC.Spread.Sheets.SheetArea.colHeader);
sheet1.setText(0, 4, "Column5", GC.Spread.Sheets.SheetArea.colHeader);
sheet1.setText(0, 0, "SPREAD-1");
sheet1.setText(1, 0, "SPREAD-2");
sheet1.setText(2, 0, "SPREAD-3");
var d = new Date();
d.setFullYear(2006, 8, 1);
sheet1.setValue(0, 1, d);
d.setFullYear(2006, 8, 2);
sheet1.setValue(1, 1, d);
d.setFullYear(2006, 8, 3);
sheet1.setValue(2, 1, d);
sheet1.setColumnWidth(1, 90);
sheet1.setValue(0, 2, 123.45);
sheet1.setValue(1, 2, 99.9999);
sheet1.setValue(2, 2, 100);
sheet1.setValue(0, 3, true);
sheet1.setValue(1, 3, false);
sheet1.setValue(2, 3, true);
sheet1.setValue(0, 4, "aaa");
sheet1.setValue(1, 4, "bbb");
sheet1.setValue(2, 4, "ccc");

$("#button1").click(function () {
    //Save all data on the first sheet in a csv format.
    window.CSVString = spread.getSheet(0).getCsv(0, 0, spread.getSheet(0).getRowCount(), spread.getSheet(0).getColumnCount(), "\r", ",");
    alert(CSVString);
});

$("#button2").click(function () {
    //Load the saved csv file on the second sheet.
    spread.getSheet(1).setCsv(0, 0, window.CSVString, "\r", ",");
});

//Add button controls to page
<input type="button" id="button1" value="button1"/>
<input type="button" id="button2" value="button2"/>