How to parse Excel (XLS) file in Javascript/HTML5

Old question, but I should note that the general task of parsing XLS files from javascript is tedious and difficult but not impossible.

I have basic parsers implemented in pure JS:

• http://oss.sheetjs.com/js-xls/ (XLS files, what you wanted)
• http://oss.sheetjs.com/js-xlsx/ (XLSX/XLSM/XLSB files)

Both pages are HTML5 File API-driven XLS/XLSX parsers (you can drag-drop your file and it will print out the data in the cells in a comma-separated list). You can also generate JSON objects (assuming the first row is a header row).

The test suite http://oss.sheetjs.com/ shows a version that uses XHR to get and parse files.

Below Function converts the Excel sheet (XLSX format) data to JSON. you can add promise to the function.

<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/jszip.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/xlsx.js"></script>
<script>
var ExcelToJSON = function() {

  this.parseExcel = function(file) {
    var reader = new FileReader();

    reader.onload = function(e) {
      var data = e.target.result;
      var workbook = XLSX.read(data, {
        type: 'binary'
      });

      workbook.SheetNames.forEach(function(sheetName) {
        // Here is your object
        var XL_row_object = XLSX.utils.sheet_to_row_object_array(workbook.Sheets[sheetName]);
        var json_object = JSON.stringify(XL_row_object);
        console.log(json_object);

      })

    };

    reader.onerror = function(ex) {
      console.log(ex);
    };

    reader.readAsBinaryString(file);
  };
};
</script>

Below post has the code for XLS format Excel to JSON javascript code?