ASP.NET

 Private Sub MyMessage(ByVal strMsg As String)<br />
            Dim strScript As String = "<script language=JavaScript> "<br />
            ' strScript += "window.onload=alert('hai alert');"<br />
            'strScript += "alert(""" & strMsg & """);"<br />
            If (strMsg <> "") Then<br />
                If (strMsg = "CLOSE") Then<br />
                    strScript += "window.close();"<br />
                Else<br />
                    strScript += strMsg<br />
                End If<br />
            End If<br />
<br />
            'strScript += "return false;"<br />
            strScript += "</script>"<br />
            'Response.Write(strScript)<br />
            If (Not Page.IsStartupScriptRegistered("clientScript")) Then<br />
                Page.RegisterStartupScript("clientScript", strScript)<br />
                'Page.RegisterClientScriptBlock("clientScript", strScript)<br />
            End If<br />
        End Sub

void OnAuthenticate(object sender, AuthenticateEventArgs e)
{
  if (Login1.UserName == "bill" && Login1.Password == "evans")
     e.Authenticated = true;
  else
     e.Authenticated = false;
}