function formatTime() {
  now = new Date();
  hour = now.getHours();
  min = now.getMinutes();
  sec = now.getSeconds();

  
    if (min <= 9) {
      min = "0" + min;
    }
    if (sec <= 9) {
      sec = "0" + sec;
    }
    if (hour > 12) {
      hour = hour - 12;
      add = " p.m.";
    } else {
      hour = hour;
      add = " a.m.";
    }
    if (hour == 12) {
      add = " p.m.";
    }
    if (hour == 00) {
      hour = "12";
    }

    document.guestform.TT.value = ((hour<=9) ? "0" + hour : hour) + ":" + min + ":" + sec + add;
  
  setTimeout("formatTime()", 1000);
}

window.onload=formatTime;