XML Standards News;
New Working Drafts Galore!

February 2000, brings us a host of new working drafts.  These include:

• XML Linking Language (XLink) 
• XML Base (XBase)
• User Interface for CSS3
• The Platform for Privacy Preferences 1.0 (P3P1.0) Specification
• Mathematical Markup Language (MathML) Version 2.0
• XHTML™ Basic
• XML-Signature Syntax and Processing
• Document Object Model (DOM) Requirements

Working Draft for Platform for Privacy Preferences V1.0

P3P version 1.0 is a protocol designed to meet two goals.  First P3P will enable Web sites to specify their data-collection practices in a standardized, machine-readable XML format known as a P3P policy.  Second, P3P will inform Web users of the data-collection practices of the Web sites they "visit".  P3P will inform users about how data will be collected, how data will be used, and what options are possible.

The P3P specification includes the following:

• A standard schema for data a Web site may wish to collect, known as the "P3P base data schema"
• A standard set of uses, recipients, data categories, and other privacy disclosures
• An XML format for expressing a privacy policy
• A means of associating privacy policies with Web pages or sites
• A mechanism for transporting P3P policies over HTTP

The scenarios presented in the P3P specification indicate that eventually P3P will be implemented in both browsers and Web servers.  The browser will enable the user to specify privacy preferences, will read the privacy policies of each Web page, and will provide feedback to the user.

XLink Posts a New Working Draft on February 21, 2000

The XML Linking Working Group continues marching toward a Recommendation.  They posted a working draft on December 20, 1999,  another one on January 19, 2000 and a third working draft in late February.

The specification "defines the XML Linking Language (XLink), which allows elements to be inserted into XML documents in order to create and describe links between resources. It uses XML syntax to create structures that can describe the simple unidirectional hyperlinks of today's HTML as well as more sophisticated links."

The XLink Specification states that XLink is designed to be applied in  hypertext systems. Hyperlinks defined using XLink can be presented to humans for use and actuation. XLink is also applicable to links that are entirely machine-processed.  This version of the working draft provides a new glossary of terms, many more examples, and refinement of some concepts. For example, clear definitions have been added for terms like resource, remote resource, starting resource, participating resource, and sub-resource.

This new working draft also details the issues in applying XLink to legacy markup.  According to the draft, "Because XLink's global attributes require the use of namespace prefixes, non-XLink-based links in legacy documents cannot be made into compliant XLink constructs as they stand, even if attribute value defaulting is used. XLink advises that those designing XML markup languages that include linking constructs may wish to issue new versions that take advantage of XLink.

Introducing XMLBase!

XMLBase is a new W3C specification.  XMLBase provides syntax for including the equivalent of HTML BASE functionality generically in XML documents by defining an XML attribute named xml:base.

XMLBase has been developed as a response to the stated requirement of XLink to support HTML 4.0  linking constructs in a generic way. XMLBase allows authors to explicitly specify a document's base URI for the purpose of resolving relative URIs in links to external images, applets, form-processing programs, and style sheets.  XMLBase proposes that the functionality  be provided to generic XML applications and that the resolution of relative URIs  should be solved at the addressing (URI) level and not at the higher level of linking (XLink).  The base URI specified by xml:base sets the base URI information set property of the element on which this attribute occurs, and to its descendants except where further xml:base attributes are applied.  The following example shows the use of xml:base to resolve the URI specified in anchor tags.

<?xml version="1.0"?>
<html xmlns="http://www.w3.org/TR/xhtml1/strict"
     xml:base="http://somewhere.org">
<head>
   <title>Virtual Library</title>
</head>
<body>
  <p>See <a href="new.xml">what's new</a>!</p>
  <p>Check out the hot picks of the day!</p>
  <ol xml:base="/hotpicks">
    <li><a href="pick1.xml">Hot Pick #1</a></li>
    <li><a href="pick2.xml">Hot Pick #2</a></li>
    <li><a href="pick3.xml">Hot Pick #3</a></li>
  </ol>
</body>
</html>

XHTML™ Basic

XHTML™ Basic is new this month as well.  XHTML™ Basic is a result of the ongoing work of the XHTML working group.  XHTML™ Basic is a subset of XHTML 1.1. It includes the minimal set of modules required to be an XHTML Family document type, as well as images, forms, and basic tables. It is designed for light-weight Web clients such as mobile phones, PDAs, pagers, and settop boxes.

XHTML™ Basic is implemented using XHTML modules as defined in "Modularization of XHTML" [XHTMLMOD].  Although XHTML Basic can be considered to be a "lite" version of XHTML, it is designed to be rich enough for authoring.