![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
Correction status：qualified
Teacher's comments：
Collection
Collection
代码：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>彩虹球</title>
<style type="text/css">
ul {
padding: 0;
margin: 0;
width: 450px;
border: 0px dashed #666;
padding: 10px 5px;
}
ul:after {
content:'';
display: block;
clear:both;
}
li {
list-style: none;
float: left;
width: 40px;
height: 40px;
line-height: 40px;
text-align: center;
border-radius: 50%;
background: skyblue;
margin-right: 5px;
}
.bg-red {background-color: red;}
.bg-orangered {background-color: orangered;}
.bg-yellow {background-color: yellow;}
.bg-mediumseagreen {background-color: mediumseagreen;}
.bg-aqua {background-color: aqua;}
.bg-mediumblue {background-color: mediumblue;}
.bg-purple {background-color: purple;}
}
</style>
</head>
<body>
<ul>
<li id="item1">1</li>
<li class="green">2</li>
<li class="red">3</li>
<li id="item2">4</li>
<li>5<img src=""></li>
<li class="black">6</li>
<li class="blue">7</li>
</ul>
</body>
</html>
<script type="text/javascript" src="http://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script>
<script type="text/javascript">
$('#item1').css('backgroundColor','red')
$('.green').addClass('bg-orangered')
$('li:nth-child(2) + li').addClass('bg-yellow')
$('li:contains("4")').addClass('bg-mediumseagreen')
$('li:has("img")').addClass('bg-aqua')
$('li:eq(5)').addClass('bg-mediumblue')
$('li:last-child').css('background-color','purple')
$('li:parent').css('color','white')
</script>点击 "运行实例" 按钮查看在线实例
