Partial Class validateform
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim valid As String = "true"
        Dim message As String = ""

        ' Set the content type
        Response.ContentType = "text/plain"
        Response.ContentEncoding = Encoding.UTF8

        If Not Request.Form("nametextbox") Is Nothing Then
            If Request.Form("nametextbox") = "" Then
                message = "Name not supplied"
                valid = "false"
            End If
        End If

        If Not Request.Form("agetextbox") Is Nothing Then
            If Request.Form("agetextbox") = "" Then
                message = "Age not supplied"
                valid = "false"
            ElseIf IsNumeric(Request.Form("agetextbox")) = False Then
                message = "Age is not a number"
                valid = "false"
            End If
        End If

        Response.Write(valid + "||" + message)
    End Sub
End Class