XHTML, which stands for eXtensible HyperText Markup Language, marries the strict syntax and capabilities of XML with the flexibility of HTML, the standard language for creating web pages. Conceived at the end of the 1990s by the World Wide Web Consortium (W3C), XHTML emerged as a reformulation of HTML 4.01 in XML, with the first specification, XHTML 1.0, officially released in January 2000. The objective was to create a more rigorous and cleaner markup language that could be reliably processed by XML parsers and would work seamlessly across various platforms and devices.
Understanding XHTML
XHTML files end with a .xhtml extension and are served with the MIME type application/xhtml+xml. They must adhere to stricter standards: elements are properly nested, tags are in lowercase, and each tag must be closed appropriately, whether with an accompanying tag or as a self-closing entity. These rules make an XHTML document well-formed, ensuring greater consistency in how browsers and other user agents interpret the content.
Software Compatibility
Many web browsers, including Chrome, Firefox, Safari, and Internet Explorer, support XHTML. Web development tools and text editors like Adobe Dreamweaver, BlueGriffon, and Notepad++ also offer robust support for creating and editing XHTML files. However, certain legacy systems might need configuration changes or additional processing capabilities to handle the MIME type correctly.
Alternatives to XHTML
With the evolution of web standards, HTML5 has become the predominant markup language, offering new features, better cross-browser compatibility, and simplifying the development process by being more lenient with syntax errors. Other XML-based languages, such as SVG for vector graphics and SMIL for multimedia integration, have also found their specific niches. Still, XHTML remains a vital part of web development, particularly for projects requiring strict markup standards or in environments that depend on XML processing capabilities.