Web Design in a Nutshell, 3rd Edition

Minimal Document Structure

This markup sample shows the structure of a minimal XHTML document as specified in the XHTML 1.0 Recommendation. It provides important context to upcoming discussions of global document structure.

<?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 xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">

      <head><title>Document Title</title>
      </head>

      <body>
        <p>Content of document...</p></body>

    </html>

Tip

This example begins with an XML declaration that identifies the version of XML and the character encoding of the document. XML declarations are encouraged for XHTML documents; however, they are not required when the character encoding is the UTF-8 default as in the above example. Because XML declarations are problematic for current browsers as of this writing, even those that are standards-compliant, they are generally omitted.

Now, take a closer look at the four major components of XHTML (and HTML) documents.

Document type declaration

    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
       "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

The document type (DOCTYPE) declaration tells the browser which DTD to use to parse the document. This example specifies XHTML Strict. If this example were an HTML document, it would use one of the HTML DTDs. The upcoming See Document Type Declaration.” section provides more information on the DTD options and uses ...