XHTML is a combination of HTML and XML. XHTML contains of all the HTML 4.01 elements combined with XML syntax. The current version of XHTML that is supported by browsers is XHTML 1.0.

There are many pages on the WWW contain HTML that is poorly written. For example, the following HTML code will work (in most browsers), even if it does not follow the HTML rules:

The XML markup has to be marked up correctly, which results in "well-formed" documents. XML was designed to describe data and HTML was designed to display data.

Today's market consists of different browser technologies, some browsers run internet on computers, and some browsers run internet on mobile phones and PDA's. The last-mentioned do not have the resources or power to interpret a "bad" markup language.

In combining HTML and XML, XHTML is a markup language that is useful now and in the future. XHTML pages can be read by all XML enabled devices AND while waiting for the rest of the world to upgrade to XML supported browsers, XHTML gives you the opportunity to write "well-formed" documents now, that work in all browsers and that are backward browser compatible!!! In fact by making your code is XHTML compliant, you no longer have to test in all browsers to make sure that the pages function!

Visit the W3C's XHTML School or visit the Resource Links page for more information.