HomeOn = new Image;
HomeOn.src = "images/sterg-b.gif";
HomeOff = new Image;
HomeOff.src = "images/ster.gif";

function switchOn(img) {
                document [img].src = eval(img + "On.src");              
        }
        
function switchOff(img) {
                document [img].src = eval(img + "Off.src");                     
        }