count down in javascript

<div align="center">
  <center>
  <table border="0">
    <tr>
      <td><script language=Javascript1.2>
// verander hieronder de kleur font en grootte van het klokje 
var tags_before_clock = "<font face='arial' size='3' color='#CCFFCC'><b> "
var tags_middle_clock = ""
if(navigator.appName == "Netscape") {
document.write('<layer id="clock"></layer><br>');
}
if (navigator.appVersion.indexOf("MSIE") != -1){
document.write('<span id="clock"></span>');
}
function upclock(){
var dte = new Date();
var hrs = dte.getHours();
var min = dte.getMinutes();
var sec = dte.getSeconds();
var col = ":";
var spc = " ";
var com = "";
if (hrs == 0) hrs=12;
if (min<=9) min="0"+min;
if (sec<=9) sec="0"+sec;
if(navigator.appName == "Netscape") {
document.clock.document.write(tags_before_clock+hrs+col+min+col+sec+tags_middle_clock+day+com+spc);
document.clock.document.close();
}
if (navigator.appVersion.indexOf("MSIE") != -1){
clock.innerHTML = tags_before_clock+hrs+col+min+col+sec+tags_middle_clock+com+com+spc;
}
}
setInterval("upclock()",200);
</script></td>
    </tr>
  </table>
  </center>
</div>

<div align="center">
  <center>
  <table border="0">
    <tr>
      <td><script language=Javascript1.2>
// verander hieronder de kleur font en grootte van het klokje 
var tags_before_clock = "<font face='arial' size='3' color='#CCFFCC'><b> "
var tags_middle_clock = ""
if(navigator.appName == "Netscape") {
document.write('<layer id="clock"></layer><br>');
}
if (navigator.appVersion.indexOf("MSIE") != -1){
document.write('<span id="clock"></span>');
}
function upclock(){
var dte = new Date();
var hrs = dte.getHours();
var min = dte.getMinutes();
var sec = dte.getSeconds();
var col = ":";
var spc = " ";
var com = "";
if (hrs == 0) hrs=12;
if (min<=9) min="0"+min;
if (sec<=9) sec="0"+sec;
if(navigator.appName == "Netscape") {
document.clock.document.write(tags_before_clock+hrs+col+min+col+sec+tags_middle_clock+day+com+spc);
document.clock.document.close();
}
if (navigator.appVersion.indexOf("MSIE") != -1){
clock.innerHTML = tags_before_clock+hrs+col+min+col+sec+tags_middle_clock+com+com+spc;
}
}
setInterval("upclock()",200);
</script></td>
    </tr>
  </table>
  </center>
</div>