在线运行代码 - 菜鸟教程

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(cainiaoplay.com)</title>
<script>
function displayResult(){
	var x=document.getElementById("mySelect").selectedIndex;
	alert(document.getElementsByTagName("option")[x].value);
}
</script>
</head>
<body>

<form>
选择你最喜欢的水果:
<select id="mySelect">
	<option value="apple">Apple</option>
	<option value="orange">Orange</option>
	<option value="pineapple">Pineapple</option>
	<option value="banana">Banana</option>
</select>
</form>
<button type="button" onclick="displayResult()">选择的水果的值。</button>

</body>
</html>
源代码

动行结果
