HTML vs. XHTML: Why HTML Wins

Published on Dec 19, 2008 (updated Oct 18, 2024), filed under development (feed). (Share this on Mastodon or Bluesky?)

This and many other posts are also available as a pretty, well-behaved ebook: On Web Development.

Document types are cool, and there are plenty of them. There are plenty, countless discussions about the “right” document type, too. Alas, these discussions may deal with irrelevant details or miss the point. A decisive factor is performance. And that suggests the choice: Use HTML 4 or, at least “formally,” HTML 5.

How does performance or load time, which we can deem critical, influence a document type decision? In comparison with valid HTML omitting optional tags, file size of XHTML documents is about 5% (large documents) to 10% (small documents) bigger, adding a realistic file size overhead of at least 400 bytes. I did several tests in that regard which I intend to publish at some point, and the numbers are pretty reliable and easy to reproduce.

That is, no matter what flavor you typically prefer—keep in mind that the popular document types basically feature the same elements—, use of HTML will mean the most benefits. Not only will you be able to save some bytes, you’ll also be free from MIME type questions and such.

Regarding XHTML, all the classical arguments for XHTML seem to be related to its interoperability potential as well as the semantic ideal XHTML 2.0 tries to achieve. However, these arguments are as of yet hypothetical and hence not practically relevant.

This site itself still uses supposed XHTML due to historical as well as consistency reasons (the English part of this site uses WordPress which suggested XHTML, too). Even though I’ve doubted whether cost of problem outweighs cost of solution, this site’s main document type is subject to change, to switch to HTML 5 just like most of my personal projects have.

About Me

I’m Jens (long: Jens Oliver Meiert), and I’m a web developer, manager, and author. I’ve worked as a technical lead and engineering manager for small and large enterprises, I’m an occasional contributor to web standards (like HTML, CSS, WCAG), and I write and review books for O’Reilly and Frontend Dogma.

I love trying things, not only in web development and engineering management, but also in other areas like philosophy. Here on meiert.com I share some of my experiences and views. (I value you being critical, interpreting charitably, and giving feedback.)