function makevisible(myid){
	myids = getreferenzes();
	for (i=0;i<myids.length;i++){
		document.getElementById(myids[i]).style.visibility="hidden";
	}
	document.getElementById(myid).style.visibility="visible";	
	return false;
}

function getreferenzes(){
	myids = new Array();
	myitems =document.getElementById('main').getElementsByTagName('div'); 
	for (i=0; i<myitems.length;i++){
		if (myitems[i].className == 'referenz'){
			myids.push(myitems[i].id);
		}else{	
		}
	}

	return myids;	
}