function swapArrow(bild){
pfeilRechts = new Image();
pfeilRechts.src = "/img/div/pfeil_r.gif";
pfeilUnten = new Image();
pfeilUnten.src = "/img/div/pfeil_u.gif";

if(bild.src.indexOf('pfeil_r.gif') == -1){
bild.src = pfeilRechts.src;
}
else{
bild.src = pfeilUnten.src;
}
}