This JavaScript works very well with both Navigator and Explorer.
The clock will display the hours and minutes from the users computer, so no time zones are required.

<SCRIPT LANGUAGE = "JavaScript">

var timerID = null;
var timerRunning = false;

function stopclock() {
  if(timerRunning)
    clearTimeout(timerID);
    timerRunning = false;
}

function startclock() {
  stopclock();
  showtime();
}

function showtime () {
        var now = new Date();
        var hours = now.getHours();
        var minutes = now.getMinutes();
        var seconds = now.getSeconds()
        var timeValue = "" + ((hours >12) ? hours -12 :hours)
        timeValue += ((minutes < 10) ? ":0" : ":") + minutes
        timeValue += ((seconds < 10) ? ":0" : ":") + seconds
        timeValue += (hours >= 12) ? " P.M." : " A.M."
        document.clock.face.value = timeValue;
        // you could also replace the above line with...
        // window.status = timeValue;
        // and have the clock display on the status bar:
        timerID = setTimeout("showtime()",1000);
        timerRunning = true;
}

</SCRIPT>

In the HTML document use the following reference...

<form NAME='clock' onSubmit='0'>
<div ALIGN=CENTER>
<input TYPE='text' NAME='face' SIZE=14 VALUE=''>
</div>
</FORM>