var imageDir = "../resources/";
        var loadList;
        var action = "off";
        function preLoad() {
                loadList = new Array("line_ra.gif");
                onImages = new Array();
                for (field in loadList){
                        onImages[field] = new Image();
                        onImages[field].src = imageDir + loadList[field];
                }
                action = "on";
        }
        function changeImage(mode){
                if (action == "on") {
                        document.images[mode].src = imageDir + mode + "a.gif";
                }
        }
        function retImage(mode){
                if (action == "on") {
                        document.images[mode].src = imageDir + mode + ".gif";
                }
        }