ASP.NET

Public Class msg<br />
    Public Shared Sub CreateMessageAlert(ByRef aspxPage As System.Web.UI.Page, _<br />
                          ByVal strMessage As String, ByVal strKey As String)<br />
        Dim strScript As String = "<script language=JavaScript>alert('" _<br />
                                            & strMessage & "')</script>"<br />
<br />
        If (Not aspxPage.IsStartupScriptRegistered(strKey)) Then<br />
            aspxPage.RegisterStartupScript(strKey, strScript)<br />
        End If<br />
    End Sub<br />
<br />
End Class 

create message box by calling that class:<br />
        strMessage = "Your request submited"<br />
        'Call separate class, passing page reference, to register Client Script:<br />
        msg.CreateMessageAlert(Me, strMessage, "strKey1")