function set_cookie(name, value, days) {
    var today = new Date();
    var expires = new Date(today.getTime() + days * 24 * 60 * 60 * 1000);
    document.cookie = name + "=" + escape(value) + "; path=/; expires=" + expires.toGMTString();
}

function cancel_event(evt) {
    evt = evt || window.event;

    evt.returnValue = false;
    evt.cancelBubble = true;
    if (evt.preventDefault) {
        evt.preventDefault();
    }
    if (evt.stopPropagation) {
        evt.stopPropagation();
    }

    return false;
}

function remove_penbar(bar_div) {
    var style = document.getElementById(bar_div).style;
    style.visibility = "hidden";
    style.display = "none";

    set_cookie(bar_div + '-hide', '1', '0.5');
}

function install_penbar(bar_div, bar_close_button) {
    if (document.getElementById && document.cookie.indexOf(bar_div + '-hide=') == -1) {
        var style = document.getElementById(bar_div).style;
        style.display = "block";
        style.visibility = "visible";

        document.getElementById(bar_close_button).onclick = function (evt) {
            remove_penbar(bar_div);
            return cancel_event(evt);
        }
    }
}