JS-dom-热身实战总结

Original 2019-01-09 22:27:49 222
abstract:<!DOCTYPE html> <html lang="en"> <head>     <meta charset="UTF-8">     <title>实战热身</title>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>实战热身</title>
    <style>
        body{
            margin: 0;
            padding: 0;
            background: #00FF00;
        }
        ul li {
            list-style: none;
            width: 30px;
            height: 30px;
            border-radius: 50%;
        }
        img{
            background-color: red;
        }
        .wap_box{
            width: 600px;
            height: 500px;
            margin: 0 auto;
            background: #2F4056;
            position: relative;
        }
        h3{
            text-align: center;
            color: #fff;
        }
        .input_box{
            width: 260px;
            position: absolute;
            left: 50%;
            margin-left: -130px;
            bottom: 0;
            text-align: center;
        }

    </style>
</head>
<body>
<div class="wap_box">
    <h3>正在跟王小花聊天...</h3>
    <div class="input_box">
        <input type="text" name="info">
        <button>发送</button>
    </div>
    <ul>

    </ul>
</div>
<script>
    //获取元素
 let input = document.getElementsByName('info')[0];
    let button = document.getElementsByTagName('button')[0];
    let ul = document.getElementsByTagName('ul')[0];
    let wap_box = document.getElementsByClassName('wap_box')[0];
    //鼠标点击事件
 button.onclick = function () {
      //  创建dom元素 createElement("li");
 let li = document.createElement('li');
      li.innerHTML = input.value;   //li插入input的value值
 // 添加dom
 ul.appendChild(li);  //将用户框显示到列表中
 // input.value = '';  //将文本框清空
 };
</script>
</body>
</html>

本节知识点:

获取dom:

dom通过name值获取: document.getElementsByName()

dom通过标签名值获取:document.getElementsByTagName()

dom通过class获取:ocument.getElementsByClassName()

点击事件:onclick

创建li标签  createElement("li");

创建一个js 变量存放 li标签

li插入input的value值

更新li标签  .appendChild(li);  

Correcting teacher:天蓬老师Correction time:2019-01-10 08:52:48
Teacher's summary:其实创建新元素并添加到页面中是很有讲究的, 有空你研究一下文档碎片

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