Mit JS-ur virker ikke!

Hej...

Hvorfor virker mit ur ikke her ??

function slaa() {
    var hours, minutes, seconds;
    var intHours, intMinutes, intSeconds;
    var today;
    today = new Date();

    intHours = today.getHours();
    intMinutes = today.getMinutes();
    intSeconds = today.getSeconds();

if (intHours == 0) {hours = "00:";}
else if (intHours < 24) {hours = intHours+":";}

if (intMinutes < 10) {minutes = "0"+intMinutes+":";}
else {minutes = intMinutes+":";}

if (intSeconds < 10) {seconds = "0"+intSeconds+" ";}
else {seconds = intSeconds+" ";}

    timeString = hours+minutes+seconds;
    man_ur.innerHTML = timeString;
    window.setTimeout("slaa();", 100);
}

  window.onload = slaa;


-----------------------------------



<tr>
<td class="txt" style="padding-right:4px;">Time:</td>
<td class="txt" id="man_ur"></td>
</tr>