home = new Image();
home.src = '/img/navOff/home.gif';
home_on = new Image();
home_on.src = '/img/navOn/home.gif';

portrait = new Image();
portrait.src = '/img/navOff/portrait.gif';
portrait_on = new Image();
portrait_on.src = '/img/navOn/portrait.gif';

buecher = new Image();
buecher.src = '/img/navOff/buecher.gif';
buecher_on = new Image();
buecher_on.src = '/img/navOn/buecher.gif';

bestellen = new Image();
bestellen.src = '/img/navOff/bestellen.gif';
bestellen_on = new Image();
bestellen_on.src = '/img/navOn/bestellen.gif';

presse = new Image();
presse.src = '/img/navOff/presse.gif';
presse_on = new Image();
presse_on.src = '/img/navOn/presse.gif';
    
function imgOn(imgId) {
  document.getElementById(imgId).src = eval(imgId + "_on.src");
}

function imgOff(imgId) {
  document.getElementById(imgId).src = eval(imgId + ".src");
}

function switchImg( obj ) {
 obj.src = ( obj.src.search( /_off\./ ) != -1 ) ? obj.src.replace( /_off\./, "_on." ) : obj.src.replace( /_on\./, "_off." ); 
}