function clock(){
   setTimeout("clock()",1000);
   datec = new Date();
   y = datec.getYear();
   M = datec.getMonth()+1;
   d = datec.getDate();
   h = datec.getHours();
   m = datec.getMinutes();
   s = datec.getSeconds();
   if (h < 10) h = "0" + h;
   if (m < 10) m = "0" + m;
   if (s < 10) s = "0" + s;
   if (y < 2000) y += 1900;
   time = h + ":" + m + ":" + s;
   document.timeform.timetext.value = time;
}

   document.write('<form name="timeform" style="margin: 20px 0 130px 10px;"><input size="7" name="timetext" style="font-size: 24px; font-weight: bold; color: #fff; border: none; background-color: #000;"></form>');

clock();