SheetJS JS-XLSX In-Browser Export Demo
Example Code

  /* Generate Workbook */
  var wb = XLSX.utils.book_new();
  var ws = XLSX.utils.aoa_to_sheet([["a","b"],[1,2,3]]);
  XLSX.utils.book_append_sheet(wb, ws, "SheetJS");

  /* Trigger Download with `writeFile` */
  XLSX.writeFile(wb, "SheetJS.xlsb", {compression:true});

Download Generation Methods:

- IE6-9 require ActiveX and Windows Script support.
    The IE_SaveFile function from the included shim uses VBScript.

- IE10-11 use msSaveBlob API.

- When supported, `saveAs` will be used.

- When available, modern browsers use `URL.createObjectURL`.

Multiple Download Caveat

Some browsers warn or block attempts to download multiple files.  Chrome content
settings support whitelisting domains for automatic multiple downloads.