javascript export excel

<input type="button" onclick="tableToExcel('tablename', 'name')" value="Export to Excel">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]--></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))
}
})()