JSFiddle - React, Tailwind, and code Playground

HTML

<html>
<head>

</head>
<body>

<p>HTML to excel export</p>

<button id='btnExport'>
Export To Excel
</button>
<br>
<table id='testExportId'>
  <tr>
    <th bgcolor='red'>Firstname</th>
    <th bgcolor='red'>Lastname</th>
    <th bgcolor='red'>Savings</th>
  </tr>
  <tr>
    <td>Peter</td>
    <td>Griffin</td>
    <td>$100</td>
  </tr>
  <tr>
    <td>Lois</td>
    <td>Griffin</td>
    <td>$150</td>
  </tr>
  <tr>
    <td>Joe</td>
    <td>Swanson</td>
    <td>$300</td>
  </tr>
  <tr>
    <td>Cleveland</td>
    <td>Brown</td>
    <td>$250</td>
</tr>
</table>
<p>
Other table
</p>
<table id='testExportId2'>
  <tr>
    <th bgcolor='green'>Firstname</th>
    <th bgcolor='green'>Lastname</th>
  </tr>
  <tr>
    <td>Peter</td>
    <td>Griffin</td>
  </tr>
  <tr>
    <td>Lois</td>
    <td>Griffin</td>
  </tr>
  <tr>
    <td>Joe</td>
    <td>Swanson</td>
  </tr>
  <tr>
    <td>Cleveland</td>
    <td>Brown</td>
</tr>
</table>
</body>
</html>

CSS

table, td, th {
    border: 1px solid black;
}

table {
    border-collapse: collapse;
    width: 100%;
}

th {
    text-align: left;
}

JavaScript

$('#btnExport').click(
    function () {
        tableToExcel('testtable','test','KT-TestExport');
    }
);

function tableToExcel(table, sheetName, fileName) {

    var uri = 'data:application/vnd.ms-excel;base64,',
        templateData = '<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>',
        base64Conversion = function (s) { return window.btoa(unescape(encodeURIComponent(s))) },
        formatExcelData = function (s, c) { return s.replace(/{(\w+)}/g, function (m, p) { return c[p]; }) }

    if (!table.nodeType)
        table = document.getElementById('testExportId')
	
    var ctx = { worksheet: sheetName || 'Worksheet', table: table.innerHTML }

    var element = document.createElement('a');
    element.setAttribute('href', 'data:application/vnd.ms-excel;base64,' + base64Conversion(formatExcelData(templateData, ctx)));
    element.setAttribute('download', fileName);
    element.style.display = 'none';
    document.body.appendChild(element);
    element.click();
    document.body.removeChild(element);
	
}