Can List Elements Be Nested?

Yes. You can nest list element within each other because:

• List items can have block elements as contents.
• List elements are block elements.
• List items can have list elements as contents resulting nested list elements.

Below is a good tutorial example of using nested list elements to build a 3-level table of contents:

<?xml version="1.0" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
 <head>
  <title>Nested Lists</title>
 </head>
 <body>
  <h3>Tutorial Tips by FYIcenter.com:</h3>
  <ol>
  <li><strong>XHTML Tutorials/FAQs</strong> - 116 Entries
   <ol>
   <li>Introduction To XHTML 1.0
    <ol>
    <li>What Is XHTML?</li>
    <li>What Does an XHTML Document Look Like?</li>
    <li>What Is the Relation between XHTML and HTML?</li>
    <li>What Is the Relation between XHTML and XML?</li>
    <li>etc.</li>
    </ol>
   </li>
   <li>Introduction To Tag and Attribute Syntax
    <ol>
    <li>What Is an XHTML Element?</li>
    <li>How To Enter Comments into XHTML documents?</li>
    <li>How To Write the Opening Tag of an XHTML Element?</li>
    <li>How To Closing an XHTML Element?</li>
    <li>etc.</li>
    </ol>
   </li>
   <li>etc.</li>
   </ol>
  </li>
  <li><strong>PHP Tutorials/FAQs</strong> - 204 Entries
   <ol>
   <li>Understanding and Managing Cookies
    <ol>
    <li>What Is a Cookie?</li>
    <li>How To Send a Cookie to the Browser?</li>
    <li>How To Receive a Cookie from the Browser?</li>
    <li>etc.</li>
    </ol>
   </li>
   </ol>
  </li>
  </ol>
 </body>
</html>

If you save the above document as nested_lists.html, and view it with Internet Explorer, you will see a list tree of 3 levels as shown below:

⇒ HTML Ordered List Item Markers

⇐ HTML Definition List 'dl' Tag/Element

⇑ HTML Lists and List Items

⇑⇑ HTML Tutorials