How to specify a subroutine to call in the query string and execute it [duplicate]

Question

The query string contains the form and func variables and other data. Based on this querystring a sub customer_display has to be called.

form=customer&func=display&otherdata=12...

ASP file

<%

'how to make the following line to call customer_display
Call  form & "_" & func


Sub customer_display
  ...
End Sub

%>