:nth-of-type()
:nth-of-type(n)选择器匹配同类型中的第n个同级兄弟元素。
n可以是一个数字，一个关键字，或者一个公式。
语法
p:nth-of-type(2)
{
background:#ff0000;
}
值
例子
HTML
<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>
CSS
p:nth-of-type(2)
{
background:#ff0000;
}
执行结果
This is a heading
The first paragraph.
The second paragraph.
The third paragraph.
The fourth paragraph.