What's new in XHTML 1.1

XHTML is the evolution of HTML, and is sometimes thought of as HTML 5.  XHTML 1.1 is the latest XHTML standard at the time of this writing, having reached the official W3C Recommendation status in 2001.XHTML 1.1 evolved out of its predecessors, but along the way dropped some baggage that was holding it back and picked up a couple of new features.

In the early days, the priority was to get HTML working and get it adopted by developers. Like any technology that becomes popular, more and more sophisticated demands were made on HTML. New Web-enabled products emerged and new players appeared, including accessibility organizations. The arrival of XML technologies signaled a clear need for change - XHTML 1.0 was a conservative step forward, retaining a strong HTML legacy. Not until XHTML 1.1 do we see a standard that makes a clean break from the infancy of the Web.

What is XHTML 1.1?

The XHTML 1.1 recommendation defines a new XHTML document type that is based upon the module framework and modules defined in Modularization of XHTML which serves as the basis for future extended XHTML 'family' document types, providing a consistent, forward-looking document type cleanly separated from the deprecated, legacy functionality of HTML 4 that was brought forward into the XHTML 1.0 document types. This document type is essentially a reformulation of XHTML 1.0 Strict using XHTML Modules. This means that many facilities available in other XHTML Family document types (e.g., XHTML Frames) are not available in this document type. These other facilities are available through modules defined in Modularization of XHTML, and document authors are free to define document types based upon XHTML 1.1 that use these facilities.

With the introduction of the XHTML family of modules and document types, the W3C helped move the Internet content-development community from the days of malformed, non-standard markup into the well formed, valid world of XML. In XHTML 1.0, this move was moderated by a goal of providing for easy migration of existing, HTML 4 (or earlier) based content to XHTML and XML. With the advent of the XHTML modules defined in Modularization of XHTML, the W3C has removed support for deprecated elements and attributes from the XHTML family. These elements and attributes were largely presentation oriented functionality that is better handled via style sheets or client-specific default behavior.

Going forward, XHTML family document types will be based upon this new, more structural functional collection. In this specification, the W3C's HTML Working Group has defined an initial document type based solely upon modules. This document type is designed to be portable to a broad collection of client devices, and applicable to the majority of Internet content. Content developers who base their content upon the functionality expressed in this specification can be confident that it will be consistently portable across XHTML family conforming user agents.

The single most significant change in XHTML 1.1 is the uncoupling of data from presentation. Formatting is no longer embedded with data and can only be achieved by referencing Cascading Style Sheets (CSS). This leaves data available for easy parsing and reuse by a wide range of new non-desktop products and accessibility applications. XHTML is backwards compatible where it matters most - at the level of information. Some older browsers may not support CSS and so presentation of Web pages may not be exactly as intended, but the information on the Web page is still available. XHTML 1.1 represents a departure from both HTML 4 and XHTML 1.0 - many features were deprecated. In general, the underlying philosophy of XHTML 1.1 was define a markup language that is rich in structural functionality, but that relies upon style sheets for presentation.