//here you place the ids of every element you want.
var ids = new Array('a0','a1','a2','a3','a4');

var id_permanent = new Array();

function switchid(id){	
	hideallids();
	showdiv(id);
}

function hideallids(){
	//loop through the array and hide each element by id
	for (var i=0;i<ids.length;i++){
		hidediv(ids[i]);
	}		  
}

function hidediv(id) {
	
	if(!id_permanent[id]){
		//safe function to hide an element with a specified id
		if (document.getElementById) { // DOM3 = IE5, NS6
			document.getElementById(id).style.display = 'none';
		}
		else {
			if (document.layers) { // Netscape 4
				document.id.display = 'none';
			}
			else { // IE 4
				document.all.id.style.display = 'none';
			}
		}
	}//if
}

function showHideDivPermanent(id) {
	
	if(!id_permanent[id]){//lo devo accendere
			
		id_permanent[id] = id;	
			
		//safe function to show an element with a specified id		  
		if (document.getElementById) { // DOM3 = IE5, NS6
			document.getElementById(id).style.display = 'block';
		}
		else {
			if (document.layers) { // Netscape 4
				document.id.display = 'block';
			}
			else { // IE 4
				document.all.id.style.display = 'block';
			}
		}
	
		
	}else{//lo dv spegnere
		
		id_permanent[id] = null;
		
		//safe function to hide an element with a specified id
		if (document.getElementById) { // DOM3 = IE5, NS6
			document.getElementById(id).style.display = 'none';
		}
		else {
			if (document.layers) { // Netscape 4
				document.id.display = 'none';
			}
			else { // IE 4
				document.all.id.style.display = 'none';
			}
		}
		
	}//else lo dv spegnere
	
}

function showdiv(id) {
	//safe function to show an element with a specified id		  
	if (document.getElementById) { // DOM3 = IE5, NS6
		document.getElementById(id).style.display = 'block';
	}
	else {
		if (document.layers) { // Netscape 4
			document.id.display = 'block';
		}
		else { // IE 4
			document.all.id.style.display = 'block';
		}
	}
}