<!--
if (document.images) {
        //off (inactive) images
	var img1off = new Image()
        img1off.src = "IMAGES/img1-off.jpg"
        var img2off = new Image()
        img2off.src = "IMAGES/img2-off.jpg"
        var img3off = new Image()
        img3off.src = "IMAGES/img3-off.jpg"
        var img4off = new Image()
        img4off.src = "IMAGES/img4-off.jpg"

        //on (active) images
	var img1 = new Image()    
        img1.src = "IMAGES/img1-on.jpg"           
        var img2 = new Image()
        img2.src = "IMAGES/img2-on.jpg"
        var img3 = new Image()
        img3.src = "IMAGES/img3-on.jpg"
        var img4 = new Image()
        img4.src = "IMAGES/img4-on.jpg"
}

function turnOn(imgName) {
        if (document.images) {
                document[imgName].src = eval(imgName + ".src");
        }
}

function turnOff(imgName) {
        if (document.images) {
                document[imgName].src = eval(imgName + "off.src");
        }
}