Description: XHTML, or eXtensible Hypertext Markup Language, is a markup language that combines the features of HTML (Hypertext Markup Language) and XML (eXtensible Markup Language). Its design aims to enhance the interoperability and extensibility of web documents, allowing developers to create more structured and semantically correct pages. XHTML is based on a stricter syntax than HTML, meaning that documents must be well-formed and comply with XML rules. This includes the use of properly nested tags, the necessity to close all tags, and the distinction between uppercase and lowercase in tag names. The adoption of XHTML has been driven by the need to create web content that is accessible and compatible with different devices and platforms, making it a popular choice for web development. Although HTML5 has gained popularity and incorporated many of XHTML’s features, the latter remains relevant in certain contexts, especially in applications that require a more rigorous data structure and in environments where compatibility with XML is crucial.
History: XHTML was introduced by the World Wide Web Consortium (W3C) in 2000 as an evolution of HTML 4.01, aiming to combine the flexibility of HTML with the rigidity of XML. The first version, XHTML 1.0, was released in January 2000 and was based on HTML 4.01, allowing developers to use a stricter syntax. Over the years, several versions and modules of XHTML have been developed, but its use has declined with the arrival of HTML5 in 2014, which has integrated many of XHTML’s features.
Uses: XHTML is primarily used in web development to create documents that require a more rigorous data structure and are compatible with XML. It is especially useful in applications that need interoperability between different platforms and devices, as well as in environments where document validation is crucial. It is also used in the creation of RSS feeds and in the generation of dynamic content fed from databases.
Examples: A practical example of XHTML is the creation of a web document that uses XHTML 1.0 syntax, where all tags are properly closed and nested. For instance, a simple XHTML document might include a basic structure like:
Hello, world!
. This type of document ensures that it is well-formed and compatible with browsers that interpret XML.
