Countdown timer for online exam

<form name="counter">
<input type="text" size="8" name="d1">
<input type="text" size="8" name="d2">
<input type="hidden" size="8" name="d3">
</form>

<script>
<!--
//
 var milisec=0
 var seconds=60
var minutes=2
 document.counter.d2.value='60'

function display(){


 if (milisec<=0){
    milisec=10
    seconds-=1
 }
 if (milisec<=0){
    milisec=0
    seconds-=1
 }

 if (seconds<=0){
 seconds=60
    minutes-=1
   
 }
 if (minutes<=0){
 milisec=0
 seconds=0
    minutes=0
 } 

 else
    milisec-=1
    document.counter.d1.value=minutes
    document.counter.d2.value=seconds
    document.counter.d3.value=milisec
    setTimeout("display()",100)
}
display()
-->
</script>