function show_hide(nodeName) {
    var node = document.getElementById(nodeName);

    if(node) {
        if(node.className.match(/\bhidden\b/)) {
            node.className = node.className.replace(/\bhidden\b/, '');
        }
        else {
            node.className = node.className + " hidden ";
        }
    }

    return false;
}