var defaultDuration = 0.5;
function collapse_navbar() {
    Element.hidden($$('#related'));
}
function toggle_item_visibility(elementName, duration) {
    if (Element.visible(elementName)) {
        hide_item(elementName, duration);
    } else {
        show_item(elementName, duration);
    }
    return false;
}

function hide_item(elementName, durationLength, delay) {
    if (delay != null) {
        sleep(delay);
    }
    if (durationLength == null) {
        durationLength = defaultDuration;
    }
    new Effect.BlindUp(elementName, {
        duration: durationLength
    });
    return false;
}

function show_item(elementName, durationLength, delay) {
    if (durationLength == null) {
        durationLength = defaultDuration;
    }
    new Effect.BlindDown(elementName, {
        duration: durationLength
    });
    if (delay != null) {
        sleep(delay);
    }
    return false;
}