Select 对象定义和用法
length 属性可返回下拉列表中选项的数目。
语法
selectObject.length=number
浏览器支持
所有主要浏览器都支持 length 属性
实例
实例
显示下拉列表的选项数目:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>CPU中文网-教程(gongju88.com)</title>
<script>
function displayResult(){
alert(document.getElementById("mySelect").length);
}
</script>
</head>
<body>
<form>
<select id="mySelect">
<option>Apple</option>
<option>Pear</option>
<option>Banana</option>
<option>Orange</option>
</select>
</form>
<button type="button" onclick="displayResult()">下拉列表中有多少选项?</button>
</body>
</html>
<html>
<head>
<meta charset="utf-8">
<title>CPU中文网-教程(gongju88.com)</title>
<script>
function displayResult(){
alert(document.getElementById("mySelect").length);
}
</script>
</head>
<body>
<form>
<select id="mySelect">
<option>Apple</option>
<option>Pear</option>
<option>Banana</option>
<option>Orange</option>
</select>
</form>
<button type="button" onclick="displayResult()">下拉列表中有多少选项?</button>
</body>
</html>
Select 对象其他扩展