You can use download attribute supported by modern browsera for a anchor element. First modify your HTML by adding an invisible anchor:
<a id="dlink" style="display:none;"></a>
<input type="button" onclick="tableToExcel('tablename', 'name', 'myfile.xls')" value="Export to Excel">
Notice also that the call to function tableToExcel now has 3rd parameter – where you specify file name.
Now use this modified code of your original function:
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, filename) {
if (!table.nodeType) table = document.getElementById(table)
var ctx = { worksheet: name || 'Worksheet', table: table.innerHTML }
document.getElementById("dlink").href = uri + base64(format(template, ctx));
document.getElementById("dlink").download = filename;
document.getElementById("dlink").click();
}
})()
Notice last 3 code lines: Instead of assigning URL to window – they assign it to the new anchor, then use new download attribute to force download as the given file name and then simple call click() method of the anchor.
Give it a try.
Update – For supporting utf-8 characters
As per the comment below by @WorldSEnder, a simple meta tag in the template would make the excel support utf-8 characters like Hindi.
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 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>"