Mark Wilson I am the creator of TopXML. I am available for international and local (Australia) contracts. I am a Solution Architect/Business Analyst. I have worked in IT in several countries (NZ, Australia, South Africa, UK) building and training teams for government and very large non-governmental organizations. I am ex-Microsoft Consulting Services. I wrote the first book on Microsoft XML published in 2000 called XML Programming with VB and ASP. Most recently I have been building tools for the SEO industry. Ask me for a 37 point SEO health-checkup for your website.
We all know the history of HTML and how it came about from the pains of SGML so I'll spare
you the details you’ve heard many times before. My intent today is to discuss XHTML and its
background. In this article we'll discuss the basics of XHTML, what it is, how it originated,
how it is different from HTML, and why XHTML is necessary.
Let's start from the beginning. What is XHTML? XHTML (eXtensible Hypertext Markup Language)
is the combination of HTML and XML. They have taken the vocabulary of HTML and merged that with
the syntax of XML. Why do we need this? The growth of the World Wide Web was starting to create
"bad" HTML, i.e. web pages created in HTML without following the HTML rules. Today's browsers do
an excellent job of understanding and interpreting what a developer really means to write and
they can spend most of their processing on this task.
For example, supposed we typed the following into our favorite text editor:
<TITLE>Bad HTML
<HEAD>
<TITLE>This is really bad</TITLE>
<BODY>
<H1>BAD HTML EXAMPLE
</BODY>
If we view this in IE, we get the following:
This works if you are viewing your context in traditional browsers. But we are at the age
where we need more than the typical browser technology. With the emergence of palm devices like
cell phones and palm pilots, these devices don't have the resources or processing power to
interpret bad markup language.
Enter XML. XML (eXtensible Markup Language) is a language that ensures everything is marked
up correctly and therefore results in well-formed documents. The entire goal of XML is to create
a language that is easy to learn and use while enforcing certain rules. XML is used to describe
content, not to define how to it should be displayed or how to mark it up. In addition, you don’t
need a DTD to interpret it.
The next logical step is to take these two technologies and combine their strengths into a
language that is useful now. The result is XHTML.
