function expandMenu(num) {
    menuItem = document.getElementById("m"+num);
    subMenu = document.getElementById("sm"+num);
		
    if (subMenu.style.display=='none') {
	menuItem.style.listStyleImage='url(../../img/minus.png)';
	subMenu.style.listStyleImage='none';
	subMenu.style.display='';
    } else {
	subMenu.style.display='none';
	menuItem.style.listStyleImage='url(../../img/plus.png)';
	subMenu.style.listStyleImage='none';
    }
}