​x
 
<html>
<head>
<script type="text/javascript">
function alertIndex()
  {
  var x=document.getElementById("mySelect").selectedIndex;
  var y=document.getElementsByTagName("option");
  alert(y[x].text + " has the index of: " + y[x].index);
  }
</script>
</head>
<body>
​
<form>
请选择您喜欢的水果：
<select id="mySelect">
  <option>苹果</option>
  <option>桃子</option>
  <option>香蕉</option>
  <option>桔子</option>
</select>
<br />
<br />
<input type="button" onclick="alertIndex()" value="显示被选水果的 index">
</form>
​
</body>
</html>
​