XPath and XPointer

Chapter 1. Introducing XPath and XPointer

The XPath and XPointer specifications promulgated by the World Wide Web Consortium (W3C) aim to simplify the location of XML-based content. With software based on those two specs, you’re freed of much of the tedium of finding out if something useful is in a document, so you can simply enjoy the excitement of doing something with it.

Before getting specifically into the details of XPath or XPointer, though, you should have a handle on some concepts and other background the two specs have in common. Don’t worry, the details — and there are enough, it seems, to fill a phone directory (or this book, at least) — are coming.

Why XPath and XPointer?

Detailed answers to the following questions are implicit throughout this book and explicit in a couple of spots:

Why should I care about XPath and XPointer? What do they even do?

To answer them briefly for now, consider even a simple XML document, such as this:

<house_pet_hazards> <hazard type="cleanup"> <name>hairballs</name> <guilty_party species="cat">Dilly</guilty_party> <guilty_party species="cat">Nameless</guilty_party> <guilty_party species="cat">Katie</guilty_party> </hazard> <hazard type="cleanup"> <name>miscellaneous post-ingestion surprises</name> <guilty_party species="cat">Dilly</guilty_party> <guilty_party species="cat">Katie</guilty_party> <guilty_party species="dog">Kianu</guilty_party> <guilty_party species="snake">Mephisto</guilty_party> </hazard> <hazard type="phys_jeopardy"> <name>underfoot ...