You need to post back to the server to call a serverside sub.
Here's a VERY simple example...
Code:
<%@ Language=VBScript %>
<html>
<head>
<body>
<%
dim func
func = request("f")
select case func
case 1
serverDateTime
end select
sub serverDateTime()
response.write now
end sub
%>
<FORM method="post" action="clicktest.asp" Name="frm1">
<input name=f type=hidden value=1>
<input type=submit value="Click">
</form>
</body>
</html>