function toggleArchiveYear(year) {
    var yearLink = document.getElementById('archiveLink_'+year);
    var monthLinks = document.getElementById('archiveMonthLinks_'+year); 
    
    yearLink.innerHTML = (yearLink.innerHTML.substring(0, 1) == '+') ? '- ' + year : '+ ' + year;
    monthLinks.style.display = (monthLinks.style.display == 'block' ||
        (monthLinks.style.display == '' && monthLinks.className.indexOf('displayed') > -1)) ? 'none' : 'block';
    
    return false;
}