Obfuscate email address

function printEmail(className, first, last) {
    let emailAddress = `<a href="mailto:${first}@${last}" class="link">${first}@${last}</a>`;
    let span = document.querySelectorAll('.' + className), i;
    for (i = 0; i < span.length; ++i) {
        span[i].innerHTML = emailAddress;
    }
}

printEmail('container', 'john', 'example.com');