if (document.images) {

  image1on = new Image();
  image1on.src = "_images_home/nav_home_1on.jpg";
  image2on = new Image();
  image2on.src = "_images_home/nav_home_2on.jpg"; 
  image3on = new Image();
  image3on.src = "_images_home/nav_home_3on.jpg";
  image4on = new Image();
  image4on.src = "_images_home/nav_home_4on.jpg";
  image5on = new Image();
  image5on.src = "_images_home/nav_home_5on.jpg";
  image6on = new Image();
  image6on.src = "_images_home/nav_home_6on.jpg";
  image7on = new Image();
  image7on.src = "_images_home/nav_home_7on.jpg";
  
  image1off = new Image();
  image1off.src = "_images_home/nav_home_1off.jpg";
  image2off = new Image();
  image2off.src = "_images_home/nav_home_2off.jpg";
  image3off = new Image();
  image3off.src = "_images_home/nav_home_3off.jpg";
  image4off = new Image();
  image4off.src = "_images_home/nav_home_4off.jpg";
  image5off = new Image();
  image5off.src = "_images_home/nav_home_5off.jpg";
  image6off = new Image();
  image6off.src = "_images_home/nav_home_6off.jpg";
  image7off = new Image();
  image7off.src = "_images_home/nav_home_7off.jpg";
  
}

function changeImages() {
  if (document.images) {
    for (var i=0; i<changeImages.arguments.length; i+=2) {
      document[changeImages.arguments[i]].src = eval(changeImages.arguments[i+1] + ".src");
    }
  }
}