How to export HTML table to Excel

Hi, I've never been assigned a task to generate Excel files from scratch but somehow I've just got one and did it.

Here's the general idea of how I did it.

function generateExcel (fn, array) {
	const fileName = 'my-export.xls';
	const iframe = document.getElementsByTagName('iframe');
	const table = fn(array);
	
	if (window.navigator.userAgent.indexOf("MSIE ") > 0 || !!navigator.userAgent.match(/Trident.*rv\:11\./)) {
		//for IE
		iframe.open("txt/html", "replace").write(table);
		iframe.close();
		return iframe.execCommand("SaveAs", true, fileName);
	}
	else {
		//for browsers
		const downloadLink = document.createElement("a");
		document.body.appendChild(downloadLink);
		downloadLink.href = 'data:application/vnd.ms-excel,' + encodeURIComponent(table);
		downloadLink.download = fileName;
		downloadLink.click();
	}
}

function createStringTable (src) {
	let table = '<table width="100%">';
	//create table using src
	table += '</table>';
	return table;
}

generateExcel(createStringTable, data);

Disclaimer: this block of code produces an excel file with outdated format:xls (current version is xlsx) so when you try to open the excel file you just created, you'll get warning but it has no problem for general use cases.