your code, with a little change, is working for me:
<%@ Page Language="
VB" %>
<script runat="server">
' Insert page code here
'
</script>
<html>
<head>
<script language="javascript">
function shownext()
{
window.location.href="http://www.google.com";
}
</script>
</head>
<body>
<form id="Form1" method="post" runat="server">
<a href="javascript
:shownext();">hello </a>
</form>
</body>
</html>
----------------------
wagner reatto