myHour = 7;myMinute = 57;mySecond = 48;

function sgTime(){

  mySecond++;
 
  if(mySecond >= 60){
	myMinute++;
	mySecond = 0;
  }
  if(myMinute >= 60){
	myHour++;
	myMinute = 0;
  }
  if(myHour > 23){
	myHour = 0;
  }
	
  iSecond = mySecond+'';
  iMinute = myMinute+'';
  iHour = myHour+'';
  
  if(iSecond.length == 1){
	iSecond = '0'+iSecond;
  }

  if(iMinute.length == 1){
	iMinute = '0'+iMinute;
  }

  if(iHour > 12){
	iHour = iHour - 12;
	iPeriod = 'pm';
  }
  else{
	iPeriod = 'am';
  }
  if(iHour == 0){
  	iHour = 12;
  }
  document.getElementById('dt').innerHTML = iHour+':'+iMinute+':'+iSecond+''+iPeriod;
}