Compiler Error when requesting Querystring

[Owerrybem]

I am trying to request a querystring, take a look at this and please tell me what is wrong:<BR><BR><BR><BR>Compiler Error Message: BC30188: Declaration expected.<BR><BR>Source Error:<BR><BR> <BR><BR>Line 3: <Script Runat="Server"><BR>Line 4: dim n <BR>Line 5: n = Httpcontext.Request.Querystring("n") <BR>Line 6: Sub Button_Click( s As Object, e As EventArgs )<BR>Line 7: If IsValid Then<BR> <BR><BR>thanks<BR>I can't see what line it is bombing on, but line #7 is testing "IsValid" for a value, and I don't see "IsValid" declared (i.e. Dim IsValid as String) anywhere?