if (document.images)   {
     image1on = new Image();
     image1on.src="/img/nava2.jpg";

     image1off = new Image();
     image1off.src = "/img/nava1.jpg";

}

if (document.images)   {
     image2on = new Image();
     image2on.src="/img/navb2.jpg";

     image2off = new Image();
     image2off.src = "/img/navb1.jpg";

}

if (document.images)   {
     image3on = new Image();
     image3on.src="/img/navc2.jpg";

     image3off = new Image();
     image3off.src = "/img/navc1.jpg";

}

if (document.images)   {
     image4on = new Image();
     image4on.src="/img/navd2.jpg";

     image4off = new Image();
     image4off.src = "/img/navd1.jpg";

}

if (document.images)   {
     image5on = new Image();
     image5on.src="/img/b42.jpg";

     image5off = new Image();
     image5off.src = "/img/b4.jpg";

}

if (document.images)   {
     image6on = new Image();
     image6on.src="/img/b62.jpg";

     image6off = new Image();
     image6off.src = "/img/b6.jpg";

}

if (document.images)   {
     image7on = new Image();
     image7on.src="/img/browse2.jpg";

     image7off = new Image();
     image7off.src = "/img/browse1.jpg";

}

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");
     }
}