XPath Syntax (JNNC Technologies)

XPath uses path expressions to select nodes or node-sets in an XML document. The node is selected by following a path or steps.

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The XML Example Document

We will use the following XML document in the examples below.

<?xml version="1.0" encoding="UTF-8"?>

<bookstore>

<book>
  <title lang="en">Harry Potter</title>
  <price>29.99</price>
</book>

<book>
  <title lang="en">Learning XML</title>
  <price>39.95</price>
</book>

</bookstore>

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Selecting Nodes

XPath uses path expressions to select nodes in an XML document. The node is selected by following a path or steps. The most useful path expressions are listed below:

Expression	Description
nodename	Selects all nodes with the name "nodename"
/	Selects from the root node
//	Selects nodes in the document from the current node that match the selection no matter where they are
.	Selects the current node
..	Selects the parent of the current node
@	Selects attributes

In the table below we have listed some path expressions and the result of the expressions:

Path Expression	Result
bookstore	Selects all nodes with the name "bookstore"
/bookstore	Selects the root element bookstore Note: If the path starts with a slash ( / ) it always represents an absolute path to an element!
bookstore/book	Selects all book elements that are children of bookstore
//book	Selects all book elements no matter where they are in the document
bookstore//book	Selects all book elements that are descendant of the bookstore element, no matter where they are under the bookstore element
//@lang	Selects all attributes that are named lang Predicates Predicates are used to find a specific node or a node that contains a specific value. Predicates are always embedded in square brackets. In the table below we have listed some path expressions with predicates and the result of the expressions: Path Expression Result /bookstore/book[1] Selects the first book element that is the child of the bookstore element. Note: In IE 5,6,7,8,9 first node is[0], but according to W3C, it is [1]. To solve this problem in IE, set the SelectionLanguage to XPath: In JavaScript: xml.setProperty("SelectionLanguage","XPath"); /bookstore/book[last()] Selects the last book element that is the child of the bookstore element /bookstore/book[last()-1] Selects the last but one book element that is the child of the bookstore element /bookstore/book[position()<3] Selects the first two book elements that are children of the bookstore element //title[@lang] Selects all the title elements that have an attribute named lang //title[@lang='en'] Selects all the title elements that have a "lang" attribute with a value of "en" /bookstore/book[price>35.00] Selects all the book elements of the bookstore element that have a price element with a value greater than 35.00 /bookstore/book[price>35.00]/title Selects all the title elements of the book elements of the bookstore element that have a price element with a value greater than 35.00 Selecting Unknown Nodes XPath wildcards can be used to select unknown XML nodes. Wildcard Description * Matches any element node @* Matches any attribute node node() Matches any node of any kind In the table below we have listed some path expressions and the result of the expressions: Path Expression Result /bookstore/* Selects all the child element nodes of the bookstore element //* Selects all elements in the document //title[@*] Selects all title elements which have at least one attribute of any kind Selecting Several Paths By using the | operator in an XPath expression you can select several paths. In the table below we have listed some path expressions and the result of the expressions: Path Expression Result //book/title | //book/price Selects all the title AND price elements of all book elements //title | //price Selects all the title AND price elements in the document /bookstore/book/title | //price Selects all the title elements of the book element of the bookstore element AND all the price elements in the document Next ❯