function validar_informativo() {
  if (document.informativo.newsletter_nome.value == ""){     
  alert("You must inform your name!");
  document.informativo.newsletter_nome.focus();
  return false;
  }
  if (document.informativo.newsletter_email.value == ""){     
  alert("You must inform your e-mail!");
  document.informativo.newsletter_email.focus();
  return false;
  }
  return true;
}