html运行实例（jquery_traversing_children

代码示例：（标识：jquery_traversing_children_2）

<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" src="/jquery/jquery.js"></script>
</head>
<body>
<ul class="level-1">
  <li class="item-i">I</li>
  <li class="item-ii">II
    <ul class="level-2">
      <li class="item-a">A</li>
      <li class="item-b">B
        <ul class="level-3">
          <li class="item-1">1</li>
          <li class="item-2">2</li>
          <li class="item-3">3</li>
        </ul>
      </li>
      <li class="item-c">C</li>
    </ul>
  </li>
  <li class="item-iii">III</li>
</ul>
<script>$('ul.level-2').children().css('background-color', 'red');</script>
</body>
</html>