摘要：<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>DOM实战:模拟智能在线客服系统</title> <style type="text/css"> &n
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>DOM实战:模拟智能在线客服系统</title>
<style type="text/css">
div:nth-child(1){
width: 450px;
height: 650px;
background-color: lightskyblue;
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: #efefef;
margin: 20px auto 10px;
}
ul {
list-style-type:none;
line-height: 2em;
overflow:hidden;
padding: 15px;
}
table{
width: 90%;
height: 80px;
margin: auto;
}
textarea{
border:none;
resize:none;
background-color: lightyellow;
}
button{
width: 60px;
height: 40px;
background-color: seagreen;
color:white;
border: none;
}
button:hover{
cursor: pointer;
background-color:orange;
}
</style>
</head>
<body>
<div>
<h2>在线客服</h2>
<div>
<ul>
<li></li>
</ul>
</div>
<table>
<tr>
<td><textarea name="text" cols="50" rows="4"></textarea></td>
<td><button type="button">发送</button></td>
</tr>
</table>
</div>
</body>
<script type="text/javascript">
//获取到页面中的相关元素
let btn = document.getElementsByTagName('button')[0];
let text = document.getElementsByName(text)[0];
let list = document.getElementsByTagName('ul')[0];
let sum = 0; //计数器
</script>
</html>
批改老师：天蓬老师批改时间：2018-12-31 22:34:59
老师总结：let sum = 0; //计数器, 这里为什么要用let , 用var 是否可以呢?
