function toggleDisplay(id1, id2) {
    object = document.getElementById(id1);
    objImg = document.getElementById(id2);
    if (object.style.display=='none') {
        writeSessionCookie ("menu_id1", id1);
        writeSessionCookie ("menu_id2", id2);
        object.style.display='';
        objImg.removeAttribute("src");
        objImg.setAttribute("src", "images/collapse1_up.gif");
    } else {
        writeSessionCookie ("menu_id1", null);
        writeSessionCookie ("menu_id2", null);
        object.style.display='none';
        objImg.removeAttribute("src");
        objImg.setAttribute("src", "images/collapse1.gif");
    }
}

function keepOpen() {
    var id1 = getCookieValue("menu_id1");
    var id2 = getCookieValue("menu_id2");
    if ((id1!=null) && (id2!=null)) {
        object = document.getElementById(id1);
        objImg = document.getElementById(id2);
        if (object && objImg) {
            object.style.display='';
            objImg.removeAttribute("src");
            objImg.setAttribute("src", "images/collapse1_up.gif");
        }
    }
}