What Are the XHTML Element Content Models? - XHTML Tutorials - Introduction To Element Content Syntax

There are 4 content models defined for XHTML elements:

1. EMPTY - No content. Nothing between the opening tag and the closing tag. For example:

  <br/> - "br" element has no content.
  <br></br> - Same as above.
  <meta name="Author" content="FYICenter.com"/>

2. PCDATA - Parsed Character DATA. A string of characters and character entities. Empty content is allowed in this model. But no other XHTML elements are allowed in the content.

  <!-- PCDATA: Pure character string -->
  <title>My First XHTML Document</title>

  <!-- PCDATA: Empty string -->
  <textarea rows="4" cols="40"></textarea>  

  <!-- PCDATA: Characters mixed with entities -->
  <textarea rows="4" cols="40">
    while ($i=0; $i&lt;3; %i++) print "Knock ";
  </textarea>  

3. Sub-elements only - A sequence of sub-elements. No character strings are allowed in the content.

 <!-- Sub-elements only: 
   "head" can only take sub-elements like "title"
   and "meta" -->
 <head>
  <title>My First XHTML Document</title>
  <meta name="Author" content="FYICenter.com"/>
 </head>

 <!-- Sub-elements only: 
   "tr" can only take sub-elements like "td" -->
 <tr>
  <td>Author:</td>
  <td>FYIcenter.com</td>
 </tr>

 <!-- Sub-elements only: 
   "ul" can only take sub-elements like "li" -->
 <ul>
  <li>My First XHTML Document</li>
 </ul>

4. Mixed - A mixture of PCDATA and sub-elements. Empty content is also allowed in this model.

 <!-- Mixed content: "p" is having 
   text strings mixed  an "em" element -->
 <p>The nature of <em>yin and yang</em> is relative.</p>

 <!-- Mixed content: "td" is having
   text strings mixed with a "p" element -->
 <td>Dear Visitor,
  <p>Welcome to FYIcenter.com!</p>
  Thank you.
 </td>