function switchMenu(obj, new_img, old_img) {
	var el = document.getElementById(obj);
	var new_img = document.getElementById(new_img);
	var old_img = document.getElementById(old_img);
	if ( el.style.display != "none" ) {
		el.style.display = 'none';
	}
	else {
		el.style.display = '';
	}
 new_img.style.display = '';
 old_img.style.display = 'none';
}