<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>W3Cschool教程(w3cschool.cn)</title>
<style>
p:only-child
{
background:#ff0000;
}
</style>
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<body>
<div><p>This is a paragraph.</p></div>
<div><span>This is a span.</span><p>This is a paragraph.</p></div>
<p><b>注意:</b> Internet Explorer 8以及更早版本的浏览器不支持 :only-child选择器.</p>
</body>
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