function showTime(){
    var now = new Date();
    var hours = now.getHours();
    var minutes = now.getMinutes();
    var seconds = now.getSeconds();
    var timeValue = ((hours < 10) ? '0' : '') + hours;
    timeValue  += ((minutes < 10) ? ":0" : ":") + minutes;
    timeValue  += ((seconds < 10) ? ":0" : ":") + seconds;
    if (document.getElementById('clock')) {
      document.getElementById('clock').innerHTML = timeValue;
    }
    timerID = setTimeout("showTime()", 1000);
}


function showTemperatures(what) {
  if (what == 'Celsius') {
    $('temperaturen-c').style.display = 'block';
    $('temperaturen-f').style.display = 'none';
  }
  else {
    $('temperaturen-c').style.display = 'none';
    $('temperaturen-f').style.display = 'block';
  }
}

showTime();