Extensible Hypertext Markup Language

Definition of Extensible Hypertext Markup Language

Extensible Hypertext Markup Language, or XHTML, is a reformulation of HTML as an application of the XML (Extensible Markup Language) standard. This language allows for more stringent and well-structured syntax, improving web page rendering and compatibility. The goal of XHTML is to provide a more consistent and robust platform for developing web content and applications while remaining backward-compatible with existing HTML standards.


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Key Takeaways

  1. Extensible Hypertext Markup Language (XHTML) is a reformulation of HTML4 as an XML language, combining the flexibility of HTML with the stricter syntax of XML.
  2. XHTML ensures compatibility with both current and future web browsers, as well as other user agents like screen readers and web-enabled devices.
  3. Well-formed, error-free XHTML documents enable better search engine indexing, easier maintenance and updates and better cross-platform compatibility.

Importance of Extensible Hypertext Markup Language

The term Extensible Hypertext Markup Language (XHTML) is important because it represents a reformulation of HTML as an application of the XML standard, making it a more precise and strict variant of HTML.

This offers several advantages such as enhanced interoperability, compatibility, and the ability to be parsed by XML parsers.

Furthermore, it allows web developers to create cleaner, more well-structured, and easily maintainable code while providing a consistent and accessible browsing experience across various platforms and devices.

Additionally, incorporating XML namespaces in XHTML paves the way for the integration of other XML-based languages, such as Scalable Vector Graphics (SVG) and MathML, which enables the development of more sophisticated and engaging web content.


Extensible Hypertext Markup Language, abbreviated as XHTML, serves a crucial purpose in the realm of web development and content presentation. At its core, it is a reformulation of HTML that adheres to a stricter set of rules and syntax borrowed from XML (Extensible Markup Language), thus making it cleaner, more efficient, and compatible with a wider variety of devices and applications.

By incorporating these syntactic standards, XHTML paves the way for enhanced interoperability and integration across digital platforms, ensuring seamless user experiences and smoother navigation. The primary use of XHTML is for structuring and displaying online content.

Similar to HTML, it employs tags and elements to create web pages, style elements like headings, paragraphs, tables, and multimedia such as images and videos. One advantage XHTML offers is its compatibility with both traditional HTML user agents and XML parsers, which means it can be combined with other XML-based languages—such as SVG or MathML—to enable rich, interactive, and vibrant web design.

Additionally, XHTML promotes accessibility and optimization for various devices, including screen readers, mobile phones, and search engine crawlers. This translates to improved overall performance, seamless navigation, and comprehension of the content by diverse users and technological tools alike, making XHTML an invaluable asset in creating cohesive web experiences.

Examples of Extensible Hypertext Markup Language

Extensible Hypertext Markup Language (XHTML) is a version of HTML that follows the stricter rules of XML, which makes it more robust, flexible, and compatible with different devices and applications. Here are three real-world examples of XHTML usage:

Website Development: XHTML is widely used in web development since it offers improved compatibility with various browsers and devices. Websites conforming to XHTML standards load more consistently across different browsers, making it easier for developers to create a consistent browsing experience for users.

Mobile Web Applications: As mobile devices continue to gain importance, XHTML has become essential for creating mobile-specific web applications. Its strict rules and standards make it easier for mobile devices with limited resources to render the displayed content accurately. For instance, XHTML Mobile Profile (XHTML-MP) is a commonly used markup language for developing mobile web apps, providing better compatibility with mobile browsers and devices.

Accessibility: XHTML assists in creating accessible websites that can be interpreted by screen readers and other assistive technologies for users with disabilities. By adhering to XHTML standards, web developers can ensure that their content is structured correctly and easily accessible, helping to create a more inclusive web experience for everyone.

Extensible Hypertext Markup Language (XHTML) FAQs

What is Extensible Hypertext Markup Language (XHTML)?

Extensible Hypertext Markup Language (XHTML) is a stricter and cleaner version of HTML. It combines the features of HTML and XML, allowing web designers to create more structured web pages and ensuring data compatibility with other XML-based applications.

What are the main differences between HTML and XHTML?

XHTML is a stricter version of HTML and requires more specific coding rules. For example, all elements must be closed, all attribute values must be surrounded by quotes, and all tags must be written in lowercase. These rules help ensure greater compatibility, easier maintenance, and compliance with accessibility standards.

Why would someone choose to use XHTML over HTML?

XHTML offers a more structured and standardized way of coding web pages. It promotes clean and organized code, which is easier to maintain and troubleshoot. Additionally, XHTML is XML-based, which allows for better compatibility with other XML-based applications and allows web pages to be parsed by XML parsers.

How can I convert my HTML documents to XHTML?

Converting HTML to XHTML involves adhering to the stricter rules of XHTML. Some common adjustments include ensuring all tags are lowercase, adding closing tags to all elements, and using quotes around attribute values. There are also online tools available to automate this conversion process.

Do all browsers support XHTML?

Modern web browsers have built-in support for both HTML and XHTML. However, older browsers may not support XHTML fully. It is essential to test your web pages on different browsers and versions to ensure proper rendering and compatibility.

Related Technology Terms


  • XML (eXtensible Markup Language)
  • XHTML Syntax
  • Document Object Model (DOM)
  • Cascading Style Sheets (CSS)
  • Web Standards


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