![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
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Teacher's comments：
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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>在线客服</title>
<style type="text/css">
div:nth-child(1) {
width: 450px;
height: 650px;
background-color: lightskyblue;
margin: 30px auto;
color: #333;
box-shadow: 2px 2px 2px #808080
}
h2 {
text-align: center;
margin-bottom: -10px;
}
div:nth-child(2) {
width: 400px;
height: 500px;
border: 4px double green;
background-color: #efefef;
margin: 20px auto 10px;
}
ul {
list-style: none;
line-height: 2em;
/*border: 1px solid red;*/
overflow: hidden;
padding: 15px;
}
table {
width: 90%;
height:80px;
margin: auto;
}
textarea{
/*width: 300px;*/
border: none;
resize: none;
background-color: lightyellow;
}
button {
width: 60px;
height: 40px;
background-color: seagreen;
color: white;
border: none;
/*text-align: left;*/
}
button:hover {
cursor: pointer;
background-color: orange;
}
</style>
</head>
<body>
<div>
<div>
<h2>在线客服</h2>
<div contenteditable="true">
<ul>
<li></li>
</ul>
</div>
<table>
<tr>
<td align="right"><textarea cols="50" rows="4" name="text" autofocus></textarea></td>
<td align="left"><button type=button>发送</button></td>
</tr>
</table>
</div>
</div>
<script>
//获取元素名
var list = document.getElementsByTagName('ul')[0];
var text = document.getElementsByName('text')[0];
var btn = document.getElementsByTagName('button')[0];
//累计数
var sum = 0;
btn.onclick = function () {
if (text.value.length ===0 ) {
alert('输入内容不能为空!');
return false;
}
var userComment = text.value;
text.value = '';
//创建节点
var li = document.createElement('li');
li.innerHTML = userComment;
//拼接图片和输入内容
var userPic = '<img src="../0508/images/fbb.jpg" width = "30" style="border-radius:50%">';
li.innerHTML = userPic + " " +userComment;
//插入内容到留言框中
list.appendChild(li);
sum +=1;
//客服随机回复
setTimeout(function() {
var info = ['您好!有什么可以帮您的?', '客服正忙....', '请稍候....'];
var temp = info[Math.floor(Math.random() * 3)];
var reply = document.createElement('li');
var kefuPic = '<img src="../0508/images/xln.jpg" width="30" style="border-radius:50%;">';
// reply.innerHTML = kefuPic +" " + '<span style="color:red >"' + temp + '</span>';
reply.innerHTML = '<span style="width:100 text-align:right color:red" >'+ kefuPic +" " + temp + '</span>';
list.appendChild(reply);
sum += 1;
},2000);
//如果回复内容大于10条则清空聊天窗口
if (sum > 10) {
list.innerHTML = ''; //清空内容
sum = 0; // 清空计数器
}
};
</script>
</body>
</html>点击 "运行实例" 按钮查看在线实例
通过本实例,学习到了以下知识点:
获取元素名,创建节点,添加元素,随机函数