li>Tab (&amp;#x0009;)</li>
<li>Carriage return (&amp;#x000D;)</li>
<li>Line feed (&amp;#x000A;)</li>
</ul>

<p>
The XML processor normalizes different system's line end codes into one
single line-feed character, that is passed up to the application. The XHTML
user agent in addition, must treat the following characters as whitespace:
</p>

<ul>
<li>Form feed (&amp;#x000C;)</li>
<li>Zero-width space (&amp;#x200B;)</li>
</ul>

<p>
In elements where the 'xml:space' attribute is set to 'preserve', the user
agent