Sub program that can take data called parameters (optional), execute a computation (task) and return a value.
Function is a reusable piece of code. By reusable we mean that you need to make only once but you can use it many times. for example, a function of addition on a calculator. the keywords for making a function are function, return, end function. as functions, sub routines and classes are the part of VB.net, thats why we will use a separat block for it, instead of using asp block. the tag for this block is "< SCRIPT > " Example is below
<script runat="server">
function add(a as integer, b as integer)as integer
Dim c as integer
c = a + b
return c
End function
</script>
<%
response.Write(add(3, 8))
response.Write("<BR>")
response.Write(add(73, 83))
response.Write("<BR>")
response.Write(add(45, 456))
response.Write("<BR>")
%>
<script runat="server">
function vat(price as decimal) as decimal
Dim result as decimal
result = price * 17.5/100
return result
end function
</script>
<%
response.Write(vat(100))
response.Write("<BR>")
response.Write(vat(500))
response.Write("<BR>")
response.Write(vat(1000))
response.Write("<BR>")
%>