HTML vs. XHTML: Why HTML Wins

Published on Dec 19, 2008 (updated Oct 18, 2024), filed under development, html. (Share this post, e.g., on Mastodon.)

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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 an engineering lead, guerrilla philosopher, and indie publisher. I’ve worked as a technical lead and engineering manager at various companies (e.g., Google); I’m an active web and tool developer (code optimization, digital defense), a contributor to web standards (like HTML, CSS, WCAG), and a book author (O’Reilly, Frontend Dogma).

I love trying things—in web development and engineering management, but also in politics and philosophy, where I hold to one idea in particular: that we can only be well if we take good care of everyone. Here on meiert.com I talk about some of my perspectives and experiences. (Interpret charitably but be critical—and share feedback and advice that makes my work better.)