菜鸟学堂在线工具

源代码

 
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟学堂(edu.jb51.net)</title>
<style> 
p:nth-of-type(3n+0)
{
    background:#ff0000;
}
</style>
</head>
<body>
<h1>This is a heading</h1>
<p>The first paragraph.</p>
<p>The second paragraph.</p>
<p>The third paragraph.</p>
<p>The fourth paragraph.</p>
<p>The fifth paragraph.</p>
<p>The sixth paragraph.</p>
<p>The seventh paragraph.</p>
<p>The eight paragraph.</p>
<p>The ninth paragraph.</p>
</body>
</html>

运行结果 在线运行