XHTML
Because XHTML is HTML rewritten using XML, if you are familiar with HTML, mastering XHTML shouldn't be difficult. There are a few resources you can consult to review the details and differences between HTML and XHTML, but chances are you won't need them.
HTML Home Page (http://www.w3.org/MarkUp/)— This is the main W3C Home page for Hypertext Markup Languages.
XHTML Overview (http://hotwired.lycos.com/webmonkey/00/50/index2a.html)— This is an introduction to XHTML from the Webmonkey site.
Introducing XHTML (http://www.wdvl.com/Authoring/Languages/XML/XHTML/)— This is a simple XHTML Tutorial.
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