Jump menu virker ikke

Hvad er der mon galt med nedenforstående jump menu? Der sker ingenting når man skifter option.


<script language="JavaScript" type="text/JavaScript">
<!--

function jump(sel)
{
    if (sel[sel.selectedIndex].value != "")
        location = "default.asp?cat="+sel[sel.selectedIndex].value;
}
//-->
</script>
</head>
<body style="font:10pt verdana,arial,sans-serif">

<table>
<tr>
  <td>Category: </td>
  <td>
  <select name="cat" onChange="jump(this)">
  <option selected><%=strCategory%></option>
  <%if not category1=strCategory then%><option><%=category1%></option><%end if%>
  <%if not category2=strCategory then%><option><%=category2%></option><%end if%>
  </select>