sheets.rows.cells.value Date|Number|String|Boolean

The value (content) of the cell. Numbers and dates are formatted as strings. String values are HTML-encoded.

Example - setting the cell values

<script>
var workbook = new kendo.ooxml.Workbook({
  sheets: [
      {
          rows: [
            { cells: [ { value: "Name" }, { value: "Birthday" }, { value: "Age" } ] },
            { cells: [ { value: "John" }, { value: new Date(1980, 1, 5) }, { value: 34 } ] }
          ]
      }
  ]
});
workbook.toDataURLAsync().then(function(dataURL) {
  kendo.saveAs({
    dataURI: dataURL,
    fileName: "Test.xlsx"
  });
});
</script>