function showOver(menuId){
    var menuDiv = document.getElementById('menuDiv'+menuId);
    var menuItem = document.getElementById('menuItem'+menuId);
    var menuLeft = document.getElementById('menuLeft'+menuId);
    var menuRight = document.getElementById('menuRight'+menuId);
    menuLeft.style.visibility = 'visible';  
    menuRight.style.visibility = 'visible'; 
    menuDiv.className = 'menu_on';
    menuItem.className = 'menuItemOn';
}

function hideOver(menuId){
    var menuDiv = document.getElementById('menuDiv'+menuId);
    var menuItem = document.getElementById('menuItem'+menuId);
    var menuLeft = document.getElementById('menuLeft'+menuId);
    var menuRight = document.getElementById('menuRight'+menuId);
    menuLeft.style.visibility = 'hidden';   
    menuRight.style.visibility = 'hidden';  
    menuDiv.className = 'menu';
    menuItem.className = 'menuItem';
}