XHTML: The Power Of Two Languages XHTML document structure

XHTML: The power of two languages

By Sathyan Munirathinam - 2004-01-09 Page: 1 2 3 4 5 6 7

XHTML document structure

An XHTML document consists of three main parts:

DOCTYPE
Head
Body

The basic document structure is:


<!DOCTYPE ...>

<html  ... >
<head> ... </head>
<body> ... </body>
</html>

The <head> area contains information about the document, such as ownership, copyright, and keywords; and the <body> area contains the content of the document to be displayed.

Listing 1 shows you how this structure might be used in practice:

Listing 1. An XHTML example




1.  <?xml version="1.0"?>
2.  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0   
    Transitional//EN"  "DTD/xhtml1-transitional.dtd">
3.  <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"  
                     lang="en">
4.  <head>
    <title>My XHTML Sample Page</title>

    </head>
5.  <body bgcolor="white">
    <center><h1>Welcome to XHTML !</h1></center>
    </body>
6.  </html>

Line 1: Since XHTML is HTML expressed in an XML document, it must include the initial XML declaration <?xml version="1.0"?> at the top of the document.

Line 2: XHTML documents must be identified by one of three standard sets of rules. These rules are stored in a separate document called a Document Type Declaration (DTD), and are utilized to validate the accuracy of the XHTML document structure. The purpose of a DTD is to describe, in precise terms, the language and syntax allowed in XHTML.

Line 3: The second tag in an XHTML document must include the opening <html> tag with the XML namespace identified by the xmlns=http://www.w3.org/1999/xhtml attribute. The XML namespace identifies the range of tags used by the XHTML document. It is used to ensure that names used by one DTD don't conflict with user-defined tags or tags defined in other DTDs.

Line 4: XHTML documents must include a full header area. This area contains the opening <head> tag and the title tags (<title></title>), and is then completed with the closing </head> tag.

Line 5: XHTML documents must include opening and closing <body></body> tags. Within these tags you can place your traditional HTML coding tags. To be XHTML conformant, the coding of these tags must be well-formed.

Line 6: Finally, the XHTML document is completed with the closing </html> tag.

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