小编use*_*768的帖子

window.onload = function() {
    var links = document.getElementById('subMenu').getElementsByTagName('a');
    for(var i = 0; i < links.length; i++) {
          links[i].onclick = function() {
              links[i].setAttribute('class', 'selected');
          }
    }
}

萤火虫表明:

TypeError: link[i] is undefined
 link[i].setAttribute('class', 'selected');