The solution is to use the OLE / ActiveX interface for Microsoft Excel:
var ExcelApp = new ActiveXObject("Excel.Application");
ExcelSheet = new ActiveXObject("Excel.Sheet");
// Make Excel visible through the Application object.
ExcelSheet.Application.Visible = true;
// Place some text in the first cell of the sheet.
ExcelSheet.ActiveSheet.Cells(1,1).Value = "This is column A, row 1";
// Save the sheet.
// Close Excel with the Quit method on the Application object.

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