ho due pagine, a.aspx che contiene un iframe, che richiama b.aspx
in a.asp metti
codice:
<script language="javascript" type="text/javascript">
// <!CDATA[
function b_callback(variabile)
{
alert(variabile);
}
// ]]>
</script>
in b.aspx metti
codice:
<script language="javascript" type="text/javascript">
// <!CDATA[
function return_b_callback(variabile)
{
if(parent.b_callback) parent.b_callback(variabile);
}
// ]]>
</script>
nella pagina server b.aspx.vb metti, per esempio
codice:
Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim variabile As String = DateTime.Now.ToString
Me.ClientScript.RegisterStartupScript(Me.GetType, "return_b_callback", String.Format("return_b_callback(""{0}"");", variabile), True)
End Sub