if (document.images) {
  image1on = new Image();
  image1on.src = "images/miscelaneas_esp/overs/distribuidores_on.gif";
  image2on = new Image();
  image2on.src = "images/miscelaneas_esp/overs/clientes_on.gif";
  image3on = new Image();
  image3on.src = "images/miscelaneas_esp/overs/enviar_on.gif";
  image4on = new Image();
  image4on.src = "images/miscelaneas_esp/overs/limpiar_on.gif";
  image5on = new Image();
  image5on.src = "images/miscelaneas_esp/overs/click_on.gif";

  image1off = new Image();
  image1off.src = "images/miscelaneas_esp/overs/distribuidores_off.gif";
  image2off = new Image();
  image2off.src = "images/miscelaneas_esp/overs/clientes_off.gif";
  image3off = new Image();
  image3off.src = "images/miscelaneas_esp/overs/enviar_off.gif";
  image4off = new Image();
  image4off.src = "images/miscelaneas_esp/overs/limpiar_off.gif";
  image5off = new Image();
  image5off.src = "images/miscelaneas_esp/overs/click_off.gif";

}
function turnOn(imageName) {
  if (document.images) {
    document[imageName].src = eval(imageName + "on.src");
  }
}
function turnOff(imageName) {
  if (document.images) {
    document[imageName].src = eval(imageName + "off.src");
  }
}