function toggle (div_id)
    {
    if (document.getElementById(div_id).style.display == "none")
        {
        // Turn all the other menus off
        for (i=1; i<11; i++)
            {
            if (menu = document.getElementById("menu" + i)) menu.style.display = "none";
            }

        // Turn this menu on
        document.getElementById(div_id).style.display = "";
        }
    else
        {
        // Turn div off
        document.getElementById(div_id).style.display = "none";
        }
    return false;
    }