var zentrierenX = (screen.width/2)-100; //150 ergibt sich aus Fensterbreite:2
  var zentrierenY = (screen.height/2)-55; //150 ergibt sich aus Fensterhöhe:2
  var pos = "left="+zentrierenX+",top="+zentrierenY;

            elpatre_on = new Image(); elpatre_on.src = "pics/elpatre_on.gif";
            elpatre_off = new Image(); elpatre_off.src = "pics/elpatre_small_off.gif";
            intro_on = new Image(); intro_on.src = "pics/intro_on.gif";
            intro_off = new Image(); intro_off.src = "pics/intro_off.gif";
            riddle_on = new Image(); riddle_on.src = "pics/riddle_on.gif";
            riddle_off = new Image(); riddle_off.src = "pics/riddle_off.gif";
            impressum_on = new Image(); impressum_on.src = "pics/impressum_on.gif";
            impressum_off = new Image(); impressum_off.src = "pics/impressum_off.gif";
            forum_on = new Image(); forum_on.src = "pics/forum_on.gif";
            forum_off = new Image(); forum_off.src = "pics/forum_off.gif";
            links_on = new Image(); links_on.src = "pics/ranking_on.gif";
            links_off = new Image(); links_off.src = "pics/ranking_off.gif";

    function bildan(welches) {
        ActiveImage= eval(welches+"_on.src");
        document[welches].src=ActiveImage;
    }

    function bildaus(welches) {
        DefaultImage= eval(welches+"_off.src");
        document[welches].src=DefaultImage;
    }

    function preload() {
    if (!document.images) {
        return;
    }

    var ar = new Array();
    var arguments = preload.arguments;

    for (var i=0; i<arguments.length; i++) {
        ar[i] = new Image();
        ar[i].src = arguments[i];
    }
}