JavaScript-DOM对象

核心
浏览器网页就是一个DOM树形结构！
更新Dom节点
遍历Dom节点
删除Dom节点
添加Dom节点

<div id="father">
        <h1>标题</h1>
        <p id="p1">p1</p>
        <p class="p2">p2</p>
    </div>
    <script>
        var h1 = document.getElementsByTagName('h1');
        var p1 = document.getElementById('p1');
        var p2 = document.getElementsByClassName('p2');
        var father = document.getElementById('father');

        var children = father.children;
    </script>