normal1 = new Image();
normal1.src = "files/bilder/button_referenzen_normal.gif";
hover1 = new Image();
hover1.src = "files/bilder/button_referenzen_hover.gif";
down1 = new Image();
down1.src = "files/bilder/button_referenzen_hover.gif";

normal2 = new Image();
normal2.src = "files/bilder/button_kontakt_normal.gif";
hover2 = new Image();
hover2.src = "files/bilder/button_kontakt_hover.gif";
down2 = new Image();
down2.src = "files/bilder/button_kontakt_hover.gif";

normal3 = new Image();
normal3.src = "files/bilder/button_ueber_normal.gif";
hover3 = new Image();
hover3.src = "files/bilder/button_ueber_hover.gif";
down3 = new Image();
down3.src = "files/bilder/button_ueber_hover.gif";

function hover(id,Bild) {
  document.getElementById(id).src = Bild.src;
}