function checkSubmitOnce(formulario) {
  var submitted = formulario.submitted;
  if (submitted > 0) {
    return false;
  } else {
    for (var i = 0; i < formulario.elements.length; i++) {
//      alert("elemento="+formulario.elements[i].name+" de tipo="+formulario.elements[i].type);
      if (formulario.elements[i].type == "submit") {
        formulario.elements[i].disabled = true;
      }
    }
    formulario.submitted = 1;
    document.body.style.cursor = "wait";
    return true;
  }
}

function mostrarVentana(url, alto, ancho) {
  var a=window.open(url,'','height='+alto+',width='+ancho);
}