function updateClock ()
{
  var currentTime 		= new Date ();

  var currentHours		= currentTime.getHours ();
  var currentMinutes	= currentTime.getMinutes ();
  var currentSeconds	= currentTime.getSeconds ();

  // Pad the minutes and seconds with leading zeros, if required
  currentMinutes 		= ( currentMinutes < 10 ? "0" : "" ) + currentMinutes;
  currentSeconds 		= ( currentSeconds < 10 ? "0" : "" ) + currentSeconds;

  // Choose either "AM" or "PM" as appropriate
  var timeOfDay 		= ( currentHours < 12 ) ? "AM" : "PM";

  // Convert the hours component to 12-hour format if needed
  currentHours 			= ( currentHours > 12 ) ? currentHours - 12 : currentHours;

  // Convert an hours component of "0" to "12"
  currentHours 			= ( currentHours == 0 ) ? 12 : currentHours;

  // Compose the string for display
  var currentTimeString = currentHours + ":" + currentMinutes + ":" + currentSeconds + " " + timeOfDay;

  // Update the time display
  document.getElementById("clockSpan").firstChild.nodeValue = currentTimeString;
}