if (document.images) {

bookon = new Image();
bookon.src = "img/book_right_ol.jpg";
bookoff = new Image();
bookoff.src = "img/book_right.jpg";

mythoson = new Image();
mythoson.src = "img/mm_mythos_ol.gif";
mythosoff = new Image();
mythosoff.src = "img/mm_mythos.gif";

magieon = new Image();
magieon.src = "img/mm_magie_ol.gif";
magieoff = new Image();
magieoff.src = "img/mm_magie.gif";

technikenon = new Image();
technikenon.src = "img/mm_techniken_ol.gif";
technikenoff = new Image();
technikenoff.src = "img/mm_techniken.gif";

symbolmatriceson = new Image();
symbolmatriceson.src = "img/mm_symbolmatrices_ol.gif";
symbolmatricesoff = new Image();
symbolmatricesoff.src = "img/mm_symbolmatrices.gif";

glossaron = new Image();
glossaron.src = "img/mm_glossar_ol.gif";
glossaroff = new Image();
glossaroff.src = "img/mm_glossar.gif";

downloadson = new Image();
downloadson.src = "img/mm_downloads_ol.gif";
downloadsoff = new Image();
downloadsoff.src = "img/mm_downloads.gif";

verfasseron = new Image();
verfasseron.src = "img/mm_verfasser_ol.gif";
verfasseroff = new Image();
verfasseroff.src = "img/mm_verfasser.gif";

ausbildungon = new Image();
ausbildungon.src = "img/mm_ausbildung_ol.gif";
ausbildungoff = new Image();
ausbildungoff.src = "img/mm_ausbildung.gif";

kontakton = new Image();
kontakton.src = "img/mm_kontakt_ol.gif";
kontaktoff = new Image();
kontaktoff.src = "img/mm_kontakt.gif";
}

function turnOn(imageName) {
if (document.images) {
document[imageName].src = eval(imageName + "on.src");
}
}

function turnOff(imageName) {
if (document.images) {
document[imageName].src = eval(imageName + "off.src");
}
}