function hideAllButThis(parentid, tag, id) {
    paren = document.getElementById(parentid);
    childlist = paren.getElementsByTagName(tag);
    
    for (var i = 0; i < childlist.length; i++) {
        if(childlist[i].id != id) {
            child_ol = childlist[i].getElementsByTagName('ol');
            child_ol[0].style.display = 'none';
        }
        else {
            child_ol = childlist[i].getElementsByTagName('ol');
            if(child_ol[0].style.display == 'block')
                child_ol[0].style.display = 'none';
            else
                child_ol[0].style.display = 'block';
        }
    }
}