// Show the sub-menu for the given menu item, if it exists
function ShowSubMenu(MenuID){
	MenuDiv=document.getElementById("SubMenu"+MenuID);
	if (MenuDiv!=null){
		MenuDiv.style.visibility="visible";
	}
}

// Hide the sub-menu for the given menu item, if it exists
function LeaveSubMenu(MenuID){
	MenuDiv=document.getElementById("SubMenu"+MenuID);
	if (MenuDiv!=null){
		MenuDiv.style.visibility="hidden";
	}
}