Home : Internet Terms : XHTML Definition

XHTML

Stands for "Extensible Hypertext Markup Language." XHTML is markup language used to create webpages. It is similar to HTML but uses a more strict XML-based syntax. The first version of XHTML (1.0) was standardized in 2000. For several years, XHTML was the most common language used to create websites. It has since been superseded by HTML5.

Why XHTML?

As HTML evolved over the first few decades of the web, browsers became increasingly lenient in how they parsed webpage source code. The result was that websites were rendered inconsistently between browsers. One of the main goals of XHTML was to ensure webpages looked the same across multiple browsers.

Since XHTML is based on XML rather than HTML, webpages coded in XHTML must conform to a strict XML syntax. A webpage that uses the "XHTML Strict" doctype (DTD) cannot contain any errors or invalid tags, leaving no ambiguity for the web browser. However, most XHTML sites used the "XHTML Transitional" doctype, which does not require perfect syntax and even allows HTML 4.01 tags.

From 2001 to about 2011, XHTML was the standard markup language for web development. Some developers used a strict XHTML DTD, though most used transitional doctype. Since most web developers preferred a more flexible language, the web eventually transitioned back to HTML. In 2014, HTML5 was officially recommended by the W3C. Most modern browsers still support both HTML and XHTML.

Updated: December 28, 2019

Cite this definition:

https://techterms.com/definition/xhtml

TechTerms - The Tech Terms Computer Dictionary

This page contains a technical definition of XHTML. It explains in computing terminology what XHTML means and is one of many Internet terms in the TechTerms dictionary.

All definitions on the TechTerms website are written to be technically accurate but also easy to understand. If you find this XHTML definition to be helpful, you can reference it using the citation links above. If you think a term should be updated or added to the TechTerms dictionary, please email TechTerms!

Subscribe to the TechTerms Newsletter to get featured terms and quizzes right in your inbox. You can choose to receive either a daily or weekly email.

Sign up for the free TechTerms Newsletter

How often would you like to receive an email?

You can unsubscribe at any time.
Questions? Please contact us.