if (document.images)   {
     image1on = new Image();
     image1on.src="/img/a2.png";

     image1off = new Image();
     image1off.src = "/img/a1.png";

}

if (document.images)   {
     image2on = new Image();
     image2on.src="/img/b2.png";

     image2off = new Image();
     image2off.src = "/img/b1.png";

}

if (document.images)   {
     image3on = new Image();
     image3on.src="/img/c2.png";

     image3off = new Image();
     image3off.src = "/img/c1.png";

}

if (document.images)   {
     image4on = new Image();
     image4on.src="/img/d2.png";

     image4off = new Image();
     image4off.src = "/img/d1.png";

}

if (document.images)   {
     image5on = new Image();
     image5on.src="/img/e2.png";

     image5off = new Image();
     image5off.src = "/img/e1.png";

}

if (document.images)   {
     image6on = new Image();
     image6on.src="/img/f2.png";

     image6off = new Image();
     image6off.src = "/img/f1.png";

}

if (document.images)   {
     image7on = new Image();
     image7on.src="/img/g2.png";

     image7off = new Image();
     image7off.src = "/img/g1.png";

}

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");
     }
}