Open or Create excel book by specified sheet name.

excel_test.js

var file_name = "hello.xls",
    target_sheet_name = "Hello.t",
    bin_dir = WScript.ScriptFullName.replace(WScript.ScriptName, ""),
    excel = new ActiveXObject("Excel.Application"),
    fso = new ActiveXObject("Scripting.FileSystemObject");
var path = fso.buildPath(bin_dir, file_name);
var book = (fso.FileExists(path))
  ? excel.Workbooks.Open(path)
  : excel.Workbooks.Add();
var work_sheet = (function(sheet_name) {
    for (var i = 1, sheet_names = {}; i <= book.Worksheets.Count; ++i) {
        sheet_names[book.Worksheets.Item(i).Name] = true;
    }
    if (sheet_names[sheet_name]) {
        return book.Worksheets(sheet_name);
    } else {
        var new_sheet = book.Worksheets.Add();
        new_sheet.Name = sheet_name;
        return new_sheet;
    }
})(target_sheet_name);

// modify something
work_sheet.Cells(1, 2) = "Hello";

try {
    book.SaveAs(path);
} catch (e) {WScript.Echo("no updated. " + e.message);}
finally {
    book.Close(false);
    excel.Quit();
}