function setImage(evt){
    if (document.images){
        // equalize W3C and IE event objects
        evt = (evt) ? evt : ((window.event) ? window.event : null);
        if (evt){
            // equalize W3C and IE event property
            var elem = (evt.target) ? evt.target : ((evt.srcElement) ? evt.srcElement : null);
            // filter out older browsers
            if (elem && elem.className == "rollover"){
                switch (evt.type){
                    case "mouseover":
                        elem.src = imagesOver[elem.id].src;
                        break;
                    case "mouseout":
                        elem.src = imagesNormal[elem.id].src;
                        break;
                }
            }
        }
    }
}