案例:javascript案例     状态:可编辑再运行    进入竖版
 运行结果 
x
 
1
<html>
2
<head>
3
<script type="text/javascript">
4
function selectOrange()
5
  {
6
  document.getElementById("orange").selected=true;
7
  }
8
</script>
9
</head>
10
11
<body>
12
<form>
13
请选择您喜欢的水果:
14
<select>
15
  <option id="apple">苹果</option>
16
  <option id="orange">桔子</option>
17
  <option id="pineapple" selected="selected">菠萝</option>
18
  <option id="banana">香蕉</option>
19
</select>
20
<br /><br />
21
<input type="button" onclick="selectOrange()" value="选择桔子">
22
</form>
23
</body>
24
</html>
25