代码示例:(标识:jsck_nodelist_length)
<!DOCTYPE html>
<html>
<body>
<h1>NodeList 对象</h1>

<h2>length 属性</h2>

<!-- 这是注释节点! -->

<p>body 元素中的子节点数为:</p>
<p id="demo"></p>
<p>元素之间的空白是文本节点。注释也是节点。</p>

<script>
const nodeList = document.body.childNodes;
let number = nodeList.length;
document.getElementById("demo").innerHTML = number;
</script>

</body>
</html>
运行结果: