function open_menu(obj,visible) {
	while(obj.tagName!='LI') {
		obj=obj.parentNode;
	}
	var submenu=obj.getElementsByTagName('DIV');
	if(!submenu[0]) { return; }
	submenu=submenu[0];
	submenu.style.visibility= visible ? 'hidden' : 'visible';
	return;
}
function change_class(obj,class_name)
	{
	obj.className=class_name;
	return;
	}