function exportarXls(tableId, nombre = ''){
nombre = (nombre) ? nombre: 'spreadsheet'
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"><meta http-equiv="content-type" content="application/vnd.ms-excel; charset=UTF-8"><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]--></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]; }) }
var table = document.getElementById(tableId)
var ctx = { worksheet: nombre|| 'Worksheet', table: table.innerHTML }
var enlaceTmp = document.createElement('a');
enlaceTmp.href = uri + base64(format(template, ctx));
enlaceTmp.download = nombre+ '.xls';
enlaceTmp.click();
}
<button class="btn btn-success" onclick="exportarXls('atributoId', 'nombreArchivo')">XLS</button>