if (document.images) {
  image1on = new Image();
  image1on.src = "gif/scuola_windsurf_01red.gif";
    image2on = new Image();
  image2on.src = "gif/scuola_windsurf_02red.gif";
    image3on = new Image();
  image3on.src = "gif/scuola_windsurf_03red.gif";
    image4on = new Image();
  image4on.src = "gif/scuola_windsurf_04red.gif";
    image5on = new Image();
  image5on.src = "gif/scuola_windsurf_05red.gif";
    image6on = new Image();
  image6on.src = "gif/scuola_windsurf_06red.gif";


  image1off = new Image();
  image1off.src = "gif/scuola_windsurf_01.gif";
    image2off = new Image();
  image2off.src = "gif/scuola_windsurf_02.gif";
    image3off = new Image();
  image3off.src = "gif/scuola_windsurf_03.gif";
    image4off = new Image();
  image4off.src = "gif/scuola_windsurf_04.gif";
    image5off = new Image();
  image5off.src = "gif/scuola_windsurf_05.gif";
    image6off = new Image();
  image6off.src = "gif/scuola_windsurf_06.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");
  }
}