gistfile1.txt

const contList = document.querySelector('.contList');
const mailAddresses = []; 
contList.querySelectorAll('ul').forEach(function(node) {
    const name = node.querySelector('.firstLine').textContent.trim();
    const mail_address = node.querySelector('.mailAddress').textContent.trim();
    mailAddresses.push([name, mail_address]);
});
let csvContent = "data:text/csv;charset=utf-8,";
let rows = mailAddresses
rows.forEach(function(rowArray) {
   let row = rowArray.join(",");
   csvContent += row + "\r\n";
});
var encodedUri = encodeURI(csvContent);
window.open(encodedUri);
// http://phrogz.net/js/csv2vcard_2.html