Как изменить загрузку Excel файла в скрипте Java Script?

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<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.parse(json_object));
            jQuery( '#xlx_json' ).val( json_object );
          })
        };
        reader.onerror = function(ex) {
          console.log(ex);
        };

        reader.readAsBinaryString(file);
      };
  };
  function handleFileSelect(evt) {
    
    var files = evt.target.files; // FileList object
    var xl2json = new ExcelToJSON();
    xl2json.parseExcel(files[0]);
  }
</script>

<form enctype="multipart/form-data">
    <input id="upload" type=file  name="files[]"/>
</form>

    <textarea class="form-control" rows=35 cols=120 id="xlx_json"></textarea>
    <script>
        document.getElementById('upload').addEventListener('change', handleFileSelect, false);
    </script>