<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="box">div 1</div>
    <div id="demo">
        <p>paragraph 1</p>
        <p>paragraph 2</p>
        <p>paragraph 3</p>
        <div class="inner">
            <p>inner p</p>
        </div>
    </div>

    <script>
        //生成一个新的元素对象
        var newNode = document.createElement("div");
        newNode.innerHTML = "新的div";

        //给body添加一个新的节点子元素
        document.body.appendChild(newNode);

        //移除一些元素
        var box = document.getElementById("box");
        document.body.removeChild(box);

        //获取节点内部的子元素节点
        var childl = demo.children;
        console.log(childl);


    </script>

</body>
</html>