代码示例:(标识:dhtm_event_onchange)
<html>
<head>
<script type="text/javascript">
function preferedBrowser()
{
prefer=document.forms[0].browsers.value
alert("您浏览器互联网时喜欢使用 " + prefer)
}
</script>
</head>

<body>

<form>
请选择您喜欢的浏览器:
<select id="browsers" onchange="preferedBrowser()">
<option value="Internet Explorer">Internet Explorer
<option value="Netscape">Netscape
</select>
</form>

</body>
</html>
运行结果: