Home > Store

XPath, XLink, XPointer, and XML: A Practical Guide to Web Hyperlinking and Transclusion

Register your product to gain access to bonus material or receive a coupon.

XPath, XLink, XPointer, and XML: A Practical Guide to Web Hyperlinking and Transclusion


  • Sorry, this book is no longer in print.
Not for Sale


  • Copyright 2003
  • Edition: 1st
  • Book
  • ISBN-10: 0-201-70344-0
  • ISBN-13: 978-0-201-70344-3

The combination of Extensible Markup Language (XML) and its related interlinking standards bring a range of exciting possibilities to the realm of Internet content management. This practical reference book documents these critical standards, shifting theory into practice for today's developers who are creating tomorrow's useful, efficient, and information-rich applications and Web sites.

Blending advanced reference material with practical guidelines, this authoritative guide presents a historical overview, current developments, and future perspectives in three detailed sections. Part I provides a conceptual framework highlighting current and emerging linking technologies, hypermedia concepts, and the rationale behind the "open" Web of tomorrow. Part II covers the specifics behind the emerging core standards, and then Part III examines how these technologies can be applied and how the concepts can be put to efficient use within the world of Web site management and Web publishing.

Both detailed and authoritative, this book presents the most thorough documentation of XML's linking standards available, and it examines how today's enabling technologies are likely to change the Web of tomorrow.

Topics covered in-depth include:

  • Hypermedia concepts and alternatives to the Web
  • XML Namespaces, XML Base, XInclude, XML Information Set, XHTML, and XSLT
  • XPath, XLink, and XPointer concepts, strengths, and limitations
  • Emerging tools, applications, and environments
  • Migration strategies, from conventional models to more sophisticated linking techniques
  • Future perspectives on the XPath, XLink, and XPointer standards



Related Articles

Improving Web Linking Using XLink

Web Specifications: Rhetoric vs. Reality

Author's Site

Click below for Web Resources related to this title:
Author Web Site

Sample Content

Online Sample Chapter

XML Pointer Language  XPointer

Downloadable Sample Chapter

Click below for Sample Chapter(s) related to this title:
Sample Chapter 6

Table of Contents

List of Figures.

List of Tables.



About the Authors.


Information Linking.

The Web.




1. Current Technology.

The Internet Environment.

Connecting to the Internet.

How the Internet Works.

The World Wide Web.

Information Linking in the WWW.

The Web's Linking Model.

A Broader View of Linking in the Web.

Shortcomings of the Web Linking Model.

Current Solutions.


2. Hypermedia Concepts and Alternatives to the Web.

What Is Hypermedia?

History of Hypermedia.

Definition of Hypermedia.

Hypermedia Concepts.

Representing Information Associations.

Formalizing Linking Concepts.

Usage Scenarios: Hypermedia Support for Information Utilization.

Scenario Description.



3. Conceptual Viewpoint.

References versus Links.

Resource Identification: URL, URI, and URN.

Persistence of Identifiers and References.

Persistence of Identifiers.

Persistence of References.

Third-Party Links and Linkbases.

Multi-Ended Links.

Generic Links.

Typed Links.



4. Related Technologies.

XML Core Standards.

XML Namespaces.

XML Base.

XML Inclusions.

XML External Entities.


XML Information Set.

Extensible Hypertext Markup Language.

Extensible Stylesheet Language.

XSL Transformations.

XSL Formatting Objects.

Resource Description Framework.


5. XML Path Language.

General Model.

Root Node.

Element Node.

Attribute Node.

Namespace Node.

Processing Instruction Node.

Comment Node.

Text Node.


Location Paths.

Location Steps.


Node Tests.






Boolean Functions.

Number Functions.

String Functions.

Node Set Functions.


Future Developments.


6. XML Pointer Language.

General Model.

XPointer Data Model.

XPointer Data Model Examples.

XPointer Forms.

Bare Names.

Child Sequences.

Full XPointers.


Using XPointers.

XPointer Character Escaping.

XPointers and Namespaces.

How to Compose XPointers.


Future Developments.


7. XML Linking Language.

Embedding Links into XML Documents.

Link Types and Element Types.

XLink Link Types.

XLink Element Types.


Element Type Attribute.

Locator Attribute.

Semantic Attributes.

Behavior Attributes.

Traversal Attributes.

Interpretation of XLinks.




XLink Element and Attribute Declaration.

Extending XLink.

Using XLink for Linkbases.

The Future of XLink.



8. Authoring Aspects.

Practical Issues.

Lack of Presentation Semantics.

Unclear Processing Model.

Tool Support.

Loss of Context.

Legal Issues.

More Complex Authoring.

Emerging Support for XLink and XPointer.

Support in Existing Browsers.

Parsers and Code Libraries.

Hand-Coded Support.

Development Tools.

Authoring Approaches.

Identifying Things to Link.

Controlling Linking and Ensuring Link Integrity.

Link Semantics.

Accessibility and Usability.


9. Transitioning to a New Model.

Alternative Approaches.



Example Strategies.

Internal Hybrid, External No Change.

Internal Hybrid, External Hybrid.

Content Negotiation.

Migration of Content.

Building New Sites.


Index. 0201703440T07112002


The Web has been growing and evolving at a phenomenal rate since its emergence in the early 1990s. Part of this evolution has been the development of increasingly sophisticated technologies and their utilization in developing complex applications. While the technical foundations have remained relatively unchanged (URLs and HTTP have remained stable for some time, and only HTML has changed frequently), the emergence of XML as a new format for the representation of content, along with a sequence of related developments like XLink, has heralded a substantial change in the way content can be managed. The most significant of these changes is with respect to the hypermedia functionality that is enabled by these new technologies, particularly the richer linking and navigation models.

The title of this book includes the word transclusion--from Ted Nelson's work on the Xanadu system 1995--which describes an approach to including content via references that retain the original context. "Transclusion" and "transcopyright" are two of the basic features of the Xanadu system, and the Web will definitely become more Xanadu-like in the coming years. Furthermore, the Web's new hypermedia functionality will make its structure more complex, but also richer, more usable, and more informative. We believe that this book will provide an effective guide to this development in the coming years.

Purpose of the Book

Our purpose in writing this book has been to explore and illustrate the possible hypermedia functionality introduced into the Web's architecture by XML and the accompanying XLink and XPointer standards. Today's focus in the use of XML is its application-specific data-structuring capabilities. However, we believe that by effective use of XLink and XPointer in conjunction with XML, we can create hypermedia-rich applications, which will be more usable and effective than those created using the current content-based HTML hypermedia model.

The book describes the new hypermedia features of the Xlink- and XPointer-enabled Web from both a conceptual point of view and a practical perspective. A conceptual view allows us to understand the types of advanced changes enabled by these technologies, and the implications of these changes for creating effective, maintainable, and usable applications. A practical perspective allows us to understand how these technologies are actually applied by developers, as well as to examine issues related to current tools, environments, and standardization processes.

The Book's Audience

We believe that XML, Xlink, and Xpointer and, in particular, the new hypermedia functionality enabled by these technologies will fundamentally change the Web. This book focuses on understanding and leveraging these changes and should therefore be interesting and useful for many people:

  • Web authors, developers, and project managers. So far, this group has been limited by HTML's primitive linking mechanism and, for many applications, an understanding of this new hypermedia functionality will be beneficial. It will enable them to produce more sophisticated applications, both in terms of the way the content that underpins their site is managed and in terms of the functionality that can be created in the application front-end. This book provides an overview of the technology and presents concrete implementation strategies. To assist Web authors, developers, and project managers in being backwards-compatible, the book also provides transition strategies.
  • Web users. In many cases, Web users are very interested in what the future of Web technology can bring them. In particular, updated features are often the main motivation for upgrading to a newer version of a browser or other software, so Web users should be well informed about the improvements available with the most recent software.
  • Students. In courses as diverse as information studies, software engineering, information systems, and library studies, students will benefit from understanding how the Web is likely to evolve in the future--particularly with respect to the way information is represented, managed, accessed, and used.

The Book's Content

In this preface we discuss the changes in the Web and the role that emerging standards can play in developing a richer and more usable Web. In the induction, we elaborate on this idea by exploring the emerging standards and, in particular, consider what we mean by information linking and the role it plays within the Web. Essentially, the introduction provides a context for the broad focus of the book.

The rest of the book is divided into three main parts. Part I focuses on a conceptual framework. It explores the Web we might wish to develop and the emerging linking technologies that may go some way toward providing it. We start in chapter 1 with a consideration of current technology. We focus on the limitations inherent in this technology, particularly with respect to linking and the implications for information handling, navigation, and retrieval. Chapter 2 provides information about the motivation for the types of changes we are promoting. We start by exploring linking issues in much more detail, looking at hypermedia concepts and some of the historical hypermedia developments, which provides useful insights into how information might be better managed. We also provide relevant definitions that clarify much of the terminology used in the rest of the book. This chapter concludes with a typical scenario that illustrates the types of Web changes that might be desirable currently.

Chapter 3 begins the process of considering the new and the emerging technologies that enable the vision we have been establishing. Rather than describing the technologies from a syntactic level (where their applicability may be difficult to put into the context of the previous chapter's discussions), we first consider standards (e.g., XPath, XPointer, and XLink) from a conceptual viewpoint, looking at the types of support the technologies provide for sophisticated linking and content management. This discussion is supported by XML fragments examples as a way of gently introducing these concepts through a process of illustration.

Then, Part II of the book gets down to the specific details of the new technologies and considers the emerging core standards in some detail. Chapter 5 begins by considering a range of foundation technologies, which provide a supporting infrastructure, if not the core technologies. For example, we look at XML, XML Namespaces, XML Base, XInclude, XML Infoset, XHTML, XSL, XSLT, XSL-FO, and RDF. Readers with a background in the newer Web technologies may wish to skip this chapter and continue directly with the discussion in the following chapters; however, readers familiar only with the more "traditional" Web technologies, such as HTML and http, should first read this chapter.

In chapters 5, 6, and 7, we look in detail at three of the key technologies that enable our vision: XPath, XPointer, and XLink. In each case, rather than simply presenting the standard, we explain the concepts, and wherever appropriate, the strengths, limitations, and ambiguities of the standard. As such, it is important that these chapters be read in conjunction with the relevant standards. This, in turn, raises an important point: The XPointer and XLink standards have been evolving continually during the writing of this book and are likely to continue to evolve. This means that you will need to be careful in interpreting some of the comments here. In particular, at the time of this writing, the current status and version of the most relevant standards are as follows:

  • XML Path Language (XPath): W3C Recommendation Clark and DeRose, 1999
  • XML Pointer Language (XPointer): W3C Candidate Recommendation DeRose et al., 2001b
  • XML Linking Language (XLink): W3C Recommendation DeRose et al., 2001a

This means that the standards as they are today are not going to change, but since adoption has been slow so far, actual implementations may differ from these standards, and the standards may have to be reworked. (This is not the way standards are supposed to work, but it may happen. For example, HTML standards for some time more or less simply tracked what the two major browser providers had already implemented.) Currently, there is no sign that this going to happen, but readers should regularly check W3C's Web site at http://www.w3.org--specifically, the technical reports page at http://www.w3.org/TR/--for the latest versions of the standards. We will also track standard development on the book's Web site (http://transcluding.com).

Finally, in Part III we look at how these technologies can be applied in order to move toward the vision we established in Part I. These discussions are in the context of current practical limitations imposed by available infrastructure, environments, and tools (or lack of tools). In chapter 8, we investigate the authoring of applications to take advantage of XLink and XPointer. Specifically, we look at some general issues affecting how we author and use XLink, then investigate the tools, applications, and environments that are beginning to emerge.

In chapter 9, we then consider some of the issues that need to be addressed in migrating from a conventional model of Web content to a model that uses the more sophisticated techniques discussed so far in the book. In the last chapter, Chapter 10, everything is drawn together, and we make some final comments, particularly with regard to our own perspectives on the future of XLink and XPointer.



Click below to download the Index file related to this title:


Submit Errata

More Information

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020