留言 节点操作案例

 
 
 
 
<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        
        body {
            padding: 100px;
        }
        
        textarea {
             200px;
            height: 100px;
            border: 1px solid pink;
            outline: none;
            resize: none;
        }
        
        ul {
            margin-top: 50px;
        }
        
        li {
             300px;
            padding: 5px;
            background-color: rgb(245, 209, 243);
            color: red;
            font-size: 14px;
            margin: 15px 0;
        }
    </style>
</head>

<body>
    <textarea name="" id=""></textarea>
    <button>发布</button>
    <ul>

    </ul>
    <script>
        //  1 获取元素
        var btn = document.querySelector('button');
        var text = document.querySelector('textarea');
        var ul = document.querySelector('ul');

        // 注册事件
        btn.onclick = function() {
            if (text.value == '') {
                alert('请输入内容...');
                return false;
            } else {
                // 创建元素
                var li = document.createElement('li');
                li.innerHTML = text.value;
                // 添加元素
                //ul.appendChild(li);
                ul.insertBefore(li, ul.children[0]);
                text.value = '';
            }

        }
    </script>
</body>

</html>
原文地址:https://www.cnblogs.com/ericblog1992/p/13052634.html