function navOn(id) {
  var obj=document.getElementById("nav_"+id);
  obj.className="nav_item_on";
  
}

function navOff(id, get_id) {
  if(get_id !== id) {
  	var obj=document.getElementById("nav_"+id);
  	obj.className="nav_item";
  }
}

function navClick(id) {
  window.location.href="http://www.bigbelly.ch/?_id="+id;
}

function fotos(id) {
	window.open("http://www.bigbelly.ch/foto.php?_id="+id, null,
	    "height=365,width=370");
}