function showtime()
    {
        alert("a");
        var now_time = new Date();
        var hours = now_time.getHours();
        var minutes = now_time.getMinutes();
        var seconds = now_time.getSeconds();
        var timer = "" + (( hours>12） ? hours-12 : hours);
//        timer += ((minutes < 10) ? ":0" : ":") + minutes;
//        timer += ((seconds < 10) ? ":0" : ":") + seconds;
//        timer += " " + ((hours > 12) ? "pm" : "am");
//        document.clock.show.value = timer;
//        setTimeout("showtime()",1000);
    }