e> elements.</dd>
<dt><code class="tag">form</code></dt>
<dd>cannot contain other <code>form</code> elements.</dd>
</dl>

<!--OddPage-->
<h1><a name="guidelines" id="guidelines">Appendix C.
HTML Compatibility Guidelines</a></h1>

<p><b>This appendix is informative.</b></p>

<p>This appendix summarizes design guidelines for authors who
wish their XHTML documents to render on existing HTML user
agents.</p>

<h2>C.1 Processing Instructions</h2>
<p>Be aware that processing instructions are rendered on some
user