normal1 = new Image(); 
normal1.src = "i/start.png"; 
highlight1 = new Image(); 
highlight1.src = "i/start_on.png"; 

normal2 = new Image(); 
normal2.src = "i/software.png"; 
highlight2 = new Image(); 
highlight2.src = "i/software_on.png"; 

normal3 = new Image(); 
normal3.src = "i/downloads.png"; 
highlight3 = new Image(); 
highlight3.src = "i/downloads_on.png"; 

normal4 = new Image(); 
normal4.src = "i/links.png"; 
highlight4 = new Image(); 
highlight4.src = "i/links_on.png"; 

normal5 = new Image(); 
normal5.src = "i/imprint.png"; 
highlight5 = new Image(); 
highlight5.src = "i/imprint_on.png"; 

function menu(nr,objekt) {
   window.document.images[nr].src = objekt.src;
}