Introduction to XHTML (Extensible Hypertext Markup Language)

XHTML, or eXtensible HTML is the new language of the web. HTML was designed years ago as the original markup language for the World Wide Web and the W3C group responsible for web standards approved XHTML as a new web standard in 2000. XHTML is designed to replace HTML and provides for much cleaner and stricter code.

All new browsers support both HTML and XHTML. XHTML is designed as a combination of XML (eXtensible Markup Language) and HTML.

Why start designing my web pages in XHTML?

XHTML is based on XML which must be marked up correctly, so the pages you designed are created more "cleanly". In addition, XML designs the structure of a document, while HTML described the design, so as more XML devices (phones, handheld devices) come on the markup, you can more easily move your website towards supporting a broad range of devices. XHTML is also backwards compatible with older browsers, so your code will be well formed and still function correctly.

With HTML, most browsers will accept code even if it is buggy, improperly formed, improperly closed, and generally a mess. XHTML, however, requires you to close your HTML tags, use lowercase, nest your tags properly and use well formed code.

Major differences you must learn when writing XHTML:

• XHTML tags must be closed
• XHTML documents must be "well written"
• XHTML tags must be in lowercase characters

Major XHTML Differences