What Happens If the XHTML "title" Element is Missing?

XHTML 1.0 requires you write the title element inside the head element. If you forget to include the title element, the XHTML validator will return an error to you. Here is how you can test this yourself.

Go the W3 XHTML validator Web site: http://validator.w3.org/. Copy and paste the following sample HTML document to the input area:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
 <head>
  <base href="http://dev.fyicenter.com/" />
  <meta name="Author" content="FYIcenter.com" />
  <meta http-equiv="Content-Type" content="text/html;
    charset=UTF-8" />
  <script type="text/javascript" src="/_local.js"></script>
  <link rel="stylesheet" type="text/css" href="/_fyi.css" />
 </head>
 <body>
 <p></p>
 </body>
</html>

Click the "Check" button, you will get the following error:

Error Line 12 column 7: end tag for "head" which is not 
  finished.
 </head>

⇒ XHTML 'meta' Elements Not Closed

⇐ Incorrect HTML 'head' Element

⇑ HTML Document Structure and Head Level Tags

⇑⇑ HTML Tutorials