​x
 
<!DOCTYPE html>
<html>
<head>
<style>
[class|=top]
{
background:yellow;
}
</style>
</head>
​
<body>
<h1 class="top-header">Welcome</h1>
<p class="top-text">Hello world!</p>
<p class="content">Are you learning CSS?</p>
​
<p><b>注释：</b>对于 IE8 及更早版本的浏览器中的 [attribute|=value]，必须声明 &lt;!DOCTYPE&gt;。</p>
​
</body>
</html>
​