function strbk (str) {
    return (str+'').replace(/[a-z]/gi, function(s){
        return String.fromCharCode(s.charCodeAt(0)+(s.toLowerCase()<'n'?13:-13));
    });
}
function mkmail(nem, prem)
{
  window.location.href = "mailto:" + strbk(prem) + "@" + strbk(nem);
}