.</p>

<p>Although overlapping is illegal in SGML, it was widely
tolerated in existing browsers.</p>

<div class="good">
<p><strong><em>CORRECT: nested elements.</em></strong></p>

<p>&lt;p&gt;here is an emphasized
&lt;em&gt;paragraph&lt;/em&gt;.&lt;/p&gt;</p>
</div>

<div class="bad">
<p><strong><em>INCORRECT: overlapping elements</em></strong></p>

<p>&lt;p&gt;here is an emphasized
&lt;em&gt;paragraph.&lt;/p&gt;&lt;/em&gt;</p>
</div>

<h2><a name="h-4.2" id="h-4.2">4.2 Element and attribute
names must be 