案例：jQuery案例     状态：可编辑再运行    进入竖版
 运行结果　
​x
 
1
<!DOCTYPE html>
2
<html>
3
<head>
4
  <script type="text/javascript" src="/js/jquery.js"></script>
5
</head>
6
​
7
<body>
8
<ul class="level-1">
9
  <li class="item-i">I</li>
10
  <li class="item-ii">II
11
    <ul class="level-2">
12
      <li class="item-a">A</li>
13
      <li class="item-b">B
14
        <ul class="level-3">
15
          <li class="item-1">1</li>
16
          <li class="item-2">2</li>
17
          <li class="item-3">3</li>
18
        </ul>
19
      </li>
20
      <li class="item-c">C</li>
21
    </ul>
22
  </li>
23
  <li class="item-iii">III</li>
24
</ul>
25
​
26
<script>
27
var item1 = $('li.item-1')[0];
28
$('li.item-ii').find( item1 ).css('background-color', 'red');
29
</script>
30
​
31
</body>
32
</html>
33
​