WordPress is based on documents written in the XHTML scripting language. XHTML 1.0 became a W3C recommendation in the year 2000. They intended to serve it as an interim technology until XHTML 2.0 could be finalized. Anyay, even eight years later XHTML 2.0 still isn’t finished. So this article uses the phrase XHTML to refer to XHTML 1.0 only.
XHTML is like HTML as both are descendants of a language called SGML. Anyway, XHTML is also descended from XML, which is a scripting language with much stricter grammar rules than HTML, and XHTML has inherited some of that discipline. XHTML is mostly differentiated from HTML by its use of a new MIME TYPE and the addition of some new syntax rules.
WordPress prints XHTML from all its internal functions, all themes are now in XHTML and so are most plugins. So, if you want to use WordPress, you should learn some XHTML as that’s where it is right now.
If you know HTML, you will be glad to know that the majority of what you know about HTML is still relevant in XHTML. The chief differences are that XHTML forces webpage authors to be more consistent and to write more legible code. There are a few syntax and grammar differences and a few HTML tags have been dropped. If you know HTML, you’ll be surprised at how easy it is to switch to XHTML, and the new XHTML rules will force you to become a better programmer!
This much, guys. For more detailed info you can look up WordPress Codex.
Hope you liked this article!