$(function() {
  $('span.mail_info').empty();
  $('span.mail_info').append($.create('a', {'href' : rot13('znvygb:vasb@urknqrp.pu')},rot13('vasb@urknqrp.pu')));
});

function rot13(text) {
  return text.replace(/[a-zA-Z]/g, function(c){ return String.fromCharCode((c<="Z"?90:122)>=(c=c.charCodeAt(0)+13)?c:c-26)});
}