html table to excel javascript

JavaScript
<script type="text/javascript">
var tableToExcel = (function() {
  var uri = 'data:application/vnd.ms-excel;base64,'
    , template = '<html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:x="urn:schemas-microsoft-com:office:excel" xmlns="http://www.w3.org/TR/REC-html40"><head><!--[if gte mso 9]><xml><x:ExcelWorkbook><x:ExcelWorksheets><x:ExcelWorksheet><x:Name>{worksheet}</x:Name><x:WorksheetOptions><x:DisplayGridlines/></x:WorksheetOptions></x:ExcelWorksheet></x:ExcelWorksheets></x:ExcelWorkbook></xml><![endif]--><meta http-equiv="content-type" content="text/plain; charset=UTF-8"/></head><body><table>{table}</table></body></html>'
    , base64 = function(s) { return window.btoa(unescape(encodeURIComponent(s))) }
    , format = function(s, c) { return s.replace(/{(\w+)}/g, function(m, p) { return c[p]; }) }
  return function(table, name) {
    if (!table.nodeType) table = document.getElementById(table)
    var ctx = {worksheet: name || 'Worksheet', table: table.innerHTML}
    window.location.href = uri + base64(format(template, ctx))
  }
})()
</script>     <button  type="button" id="export" onclick="exportTableToExcel('tblData')">Export List</button>

<script>
    function exportTableToExcel(tableID, filename = '') {
        var downloadLink;
        var dataType = 'application/vnd.ms-excel';
        var tableSelect = document.getElementById(tableID);
        var tableHTML = tableSelect.outerHTML.replace(/ /g, '%20');

        // Specify file name
        filename = filename ? filename + '.xls' : 'excel_data.xls';

        // Create download link element
        downloadLink = document.createElement("a");

        document.body.appendChild(downloadLink);

        if (navigator.msSaveOrOpenBlob) {
            var blob = new Blob(['\ufeff', tableHTML], {
                type: dataType
            });
            navigator.msSaveOrOpenBlob(blob, filename);
        } else {
            // Create a link to the file
            downloadLink.href = 'data:' + dataType + ', ' + tableHTML;
            // Setting the file name
            downloadLink.download = filename;

            //triggering the function
            downloadLink.click();
        }
    }
</script>
Source