if (document.images) {
var oneon = new Image(10, 20);
oneon.src = "media/arrow_on.gif";
var oneoff = new Image(10, 20);
oneoff.src = "media/arrow_off.gif";

var twoon = new Image(10, 20);
twoon.src = "media/arrow_on.gif";
var twooff = new Image(10, 20);
twooff.src = "media/arrow_off.gif";

var threeon = new Image(10, 20);
threeon.src = "media/arrow_on.gif";
var threeoff = new Image(10, 20);
threeoff.src = "media/arrow_off.gif";

var fouron = new Image(10, 20);
fouron.src = "media/arrow_on.gif";
var fouroff = new Image(10, 20);
fouroff.src = "media/arrow_off.gif";

var fiveon = new Image(10, 20);
fiveon.src = "media/arrow_on.gif";
var fiveoff = new Image(10, 20);
fiveoff.src = "media/arrow_off.gif";}

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

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