Kvikskift rollover problem ??

Kode 

<script type="text/javascript">
  rolls=new Array();
  rolls[0]= new Image()
  rolls[1]= new Image()
  rolls[0].src='[sti]knap1on.png';
  rolls[1].src='[sti]knap2on.png';
  function iswitch(ele,index){
    var temp=new Image();
    temp.src=ele.src;
    ele.src=rolls[index].src;
    rolls[index]=temp;
  }
</script>
<img src="[sti]knap1off.png" onmouseover="iswitch(this,0)" onmouseout="iswitch(this,0)"/>
<img src="[sti]knap2off.png" onmouseover="iswitch(this,1)" onmouseout="iswitch(this,1)"/>

Kode 

<script type="text/javascript">
  knap1on = new Image()
  knap1off = new Image()
  knap2on = new Image()
  knap2off = new Image()
  knap1on.src='[sti]knap1on.png'
  knap1off.src='[sti]knap1off.png'
  knap2on.src = '[sti]knap2on.png'
  knap2off.src = '[sti]knap2off.png'
</script>
<p class="center">
 <a href="http://www.webdesign101.dk" onmouseover="document.images.knap1.src = knap1on.src" onmouseout="document.images.knap1.src = knap1off.src">
<img src="res/knap1off.png" id="knap1" width="41" height="33" alt="link til '101'" /></a>
<a href="http://www.webdesign101.dk"
onmouseover="document.images.knap2.src = knap2on.src"
onmouseout="document.images.knap2.src = knap2off.src">
<img src="res/knap1off.png" id="knap2" width="41" height="33" 
alt="link til '101'" /></a>

</p>

Kode 

<script type="text/javascript">
function on(elm)
{
	elm.src = 'on.png';
}

function off(elm)
{
	elm.src = 'off.gif';
}
</script>
<p>
<a href="" onmouseover="on(knap1)" onmouseout="off(knap1)"><img id="knap1" src="off.gif" /></a>
<a href="" onmouseover="on(knap2)" onmouseout="off(knap2)"><img id="knap2" src="off.gif" /></a>
</p>