function showMenu(menuId)
{
    document.getElementById(menuId).style.visibility = 'visible';
}
function hideMenu(menuId, parent, evt)
{
    if (parent.contains && evt.toElement) {
        if(!parent.contains(evt.toElement));
            document.getElementById(menuId).style.visibility = 'hidden';
    }
    else if (evt.relatedTarget) {
        var isChild = false;
        var node = evt.relatedTarget;
        while(node != null) 
        {
            if(node == parent) 
            {
                isChild = true;
            }
            node = node.parentNode;
        }
        if(!isChild)
            document.getElementById(menuId).style.visibility = 'hidden';
    }
}