function hide() {
   document.getElementById('leistungen').style.visibility = "hidden";
   document.getElementById('sortiment').style.visibility = "hidden";
   document.getElementById('referenzen').style.visibility = "hidden";
   document.getElementById('ueberuns').style.visibility = "hidden";
   document.getElementById('kontakt').style.visibility = "hidden";
   document.getElementById('presse').style.visibility = "hidden";
   document.getElementById('impressum').style.visibility = "hidden";
}

function show(name) {
   document.getElementById('leistungen').style.display="none";
   document.getElementById('sortiment').style.display="none";
   document.getElementById('referenzen').style.display="none";
   document.getElementById('ueberuns').style.display="none";
   document.getElementById('kontakt').style.display="none";
   document.getElementById('presse').style.display="none";
   document.getElementById('impressum').style.display="none";
   document.getElementById('home').style.display="none";
   if(document.getElementById(name))
	   document.getElementById(name).style.display="block";
}