Class Question!?

How can I add a value to what displays from a function in my class when a user chooses an option from my drop down menu?
 
 Here is my drop down menu:

<select id="dd">
    <option>Red</option>
    <option>Yellow</option>
    <option>Green</option>
    </select>

Then here is my class:

<script runat="server">
    Class PetName
        Public FirstName As String
       
        Function GetName() As String
            Dim Whole As String
            Whole = FirstName
            Return (Whole)
        End Function
    End Class
</script>

And here i ...