function on(obj_name,new_source,description) { 
	if (document.images) {
		document.images[obj_name].src=new_source;
	}

	var div = document.getElementById("home_title");
	div.innerHTML = description;
}

function off(obj_name,new_source,description) { 
	if (document.images) {
		document.images[obj_name].src=new_source;
	}

	var div = document.getElementById("home_title");
    if (description == null) {
        div.innerHTML = 'Benvenuti in A.C.S.I.';
    } else {
        div.innerHTML = description;
    }
}