Ændrede lige mine sikkerhedsindstillinger og så kørte det bare:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"
http://www.w3.org/TR/html4/loose.dtd"><html>
<head>
<title>Vis Billede</title>
<script language="javascript" type="text/javascript">
var popVindue;
function popWin(imgUrl,hojde,bredde){
winFeatures="height="+hojde+",width="+bredde+",scrollbars";
Url=location.href.substring(0,location.href.lastIndexOf("/")+1)+imgUrl;
popVindue=window.open(Url,"VisBillede",winFeatures);
}
function closePopWin(){
if (popVindue) popVindue.close()
}
</script>
</head>
<body>
<a href="#" onmouseover="popWin('eksperten_logo_new.gif',100,150);" onmouseout="closePopWin();">Hvis musen er herover vises der et billede</a>
</body>
</html>