菜鸟教程在线编辑器

AI 编程工具

 
                <!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"> 
<title>菜鸟教程(runoob.com)</title> 
<style> 
p:only-of-type
{
	background:#ff0000;
}
</style>
</head>
<body>

<div><p>This is a paragraph.</p></div>

<div><p>This is a paragraph.</p><p>This is a paragraph.</p></div>

</body>
</html>
              