var clock;

function UpdateClock() {
   document.getElementById('clock').innerHTML = 'Clock: '+GetTime();
   clock = setTimeout("UpdateClock()", 1000);
}

function StartClock() {
   clock = setTimeout("UpdateClock()", 1000);
}

function GetTime(){
   var tDate = new Date();
   hour = ''+tDate.getHours();
   minutes = ''+tDate.getMinutes();
   seconds = ''+tDate.getSeconds();
   if(hour.length == 1){ hour = '0'+hour; }
   if(minutes.length == 1){ minutes = '0'+minutes; }
   if(seconds.length == 1){ seconds = '0'+seconds; }
   return hour+':'+minutes+':'+seconds;
}