var user;
var domain;
var suffix;

function email(user, domain, suffix)
{
document.write('<a href="' + 'mailto:' + user + '@' + domain + '.' + suffix + '">' + user + '@' + domain + '.' + suffix + '</a>');
}

email("&#110;&#105;&#107;&#97;", "&#110;&#105;&#107;&#97;&#50;&#52;", "&#101;&#117;");