if (document.images) {
  img1on = new Image();
  img1on.src = "images/home_On.gif";
  img2on = new Image();
  img2on.src = "images/company_info_On.gif";
  img3on = new Image();
  img3on.src = "images/producers_On.gif";
  img7on = new Image();
  img7on.src = "images/products_On.gif";
  img4on = new Image();
  img4on.src = "images/buyers_On.gif";
  img5on = new Image();
  img5on.src = "images/recipes_On.gif";
  img6on = new Image();
  img6on.src = "images/contact_On.gif";


  img1off = new Image();
  img1off.src = "images/home.gif";
  img2off = new Image();
  img2off.src = "images/company_info.gif";
  img3off = new Image();
  img3off.src = "images/producers.gif";
  img7off = new Image();
  img7off.src = "images/products.gif";
  img4off = new Image();
  img4off.src = "images/buyers.gif";
  img5off = new Image();
  img5off.src = "images/recipes.gif";
  img6off = new Image();
  img6off.src = "images/contact.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");
  }
}