function getById(id) {
    if (document.getElementById) 
        return document.getElementById(id); 
    else if (document.all) 
        return document.all[id]; 
    else if (document.layers) 
        return document.layers[id]; 
    else
        return null;
}

function getStyle(element) {
    if (element.style)
        return element.style;
    else
        return element;
}

function isVisible(element) {
    return (getStyle(element).visibility != 'hidden');
}

function hideElement(element) {
    getStyle(element).visibility = 'hidden';
}

function showElement(element) {
    getStyle(element).visibility = 'visible';
}

function toggleHidden(element) {
    if (isVisible(element))
        hideElement(element);
    else
        showElement(element);
}

function isExpanded(element) {
    return (getStyle(element).display != 'none');
}

function collapseElement(element) {
    getStyle(element).display = 'none';
}

function expandElement(element) {
    getStyle(element).display = 'block';
}

function toggleCollapsed(element) {
    if (isExpanded(element))
        collapseElement(element);
    else
        expandElement(element);
}