var hlt;
function showHL (id) {
    var hldef = document.getElementById ('hldefault');
    if (hldef) hldef.style.display = 'none';
    var obj = document.getElementById (id);
    if (obj) obj.style.display = 'block';
    if (hlt) clearTimeout(hlt);
}
function hideHL (id) {
    var cmd = 'showHL(\'hldefault\');';
    var obj = document.getElementById (id);
    if (obj) obj.style.display = 'none';
    if (hlt) clearTimeout(hlt);
    hlt = setTimeout (cmd, 500);
}