Extensible Hypertext Markup Language (XHTML) is an XML application intended to replace HTML and version 1 is almost identical to HTML 4.01. XHTML, unlike HTML, does not allow improper elements or formatting. However, only browsers with version 5 or later support XHTML.

W3Schools XHTML Tutorial

This tutorial on XHTML provides numerous examples and also has a "try it yourself" feature where you can edit XHTML, then click a test button to see how it works in your browser. 

David Gowan's XHTML Tutorial

David Gowan's XHTML tutorial is very basic, but it helps you understand the basic differences between HTML and XHTML.

W3 Organization XHTML Recommendation

The W3 Consortium is the definitive source for the specification. They also have a CSS validator and an XHTML validator which will scan your page and validate it's compliance to CSS or XHTML standards.

W3 Organization Validator Service

Validate your pages against the W3 Organization HTML, XHTML, and CSS standards. If your pages pass, you then have permission to use a logo on your page that signifies compliance. However, if you have developed your pages with FrontPage, they will not validate until you add the correct !DOCTYPE tag as the first line of the file.

 

Revision A

Last maintained 08/23/03