<!DOCTYPE html>
<html>
<head>
<style>
p:only-child {
background: #ff0000;
}
</style>
</head>
<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>Note:</b> Internet Explorer 8 and earlier versions do not support the :only-child selector.</p>
</body>
</html>