XPath Examples
Let's try to learn some basic XPath syntax by looking at some examples.
The XML Example Document
We will use the following XML document in the examples below.
"books.xml":
<?xml version="1.0" encoding="ISO-8859-1"?>
<bookstore>
<book category="COOKING">
<title lang="en">Everyday Italian</title>
<author>Giada De Laurentiis</author>
<year>2005</year>
<price>30.00</price>
</book>
<book category="CHILDREN">
<title lang="en">Harry Potter</title>
<author>J K. Rowling</author>
<year>2005</year>
<price>29.99</price>
</book>
<book category="WEB">
<title lang="en">XQuery Kick Start</title>
<author>James McGovern</author>
<author>Per Bothner</author>
<author>Kurt Cagle</author>
<author>James Linn</author>
<author>Vaidyanathan Nagarajan</author>
<year>2003</year>
<price>49.99</price>
</book>
<book category="WEB">
<title lang="en">Learning XML</title>
<author>Erik T. Ray</author>
<year>2003</year>
<price>39.95</price>
</book>
</bookstore>
|
View the "books.xml" file in your browser.
Selecting Nodes
Unfortunately, there are different ways of dealing with XML and XPath in
Internet Explorer based browsers and other browsers (like Mozilla based
browsers).
In our examples we have included code that should work with most major
browsers.
Select nodes for Internet Explorer based browsers
Using the Microsoft XMLDOM object to load the XML document and the
selectNodes() method to select nodes from the XML document:
xmlDoc=new ActiveXObject("Microsoft.XMLDOM");
xmlDoc.async=false;
xmlDoc.load("books.xml");
xmlDoc.selectNodes(xpath);
|
Select nodes for other browsers
Using the implementation() method of the document object to load the XML document and the
evaluate() method to select nodes from the XML document:
xmlDoc=document.implementation.createDocument("","",null);
xmlDoc.async=false;
xmlDoc.load("books.xml");
xmlDoc.evaluate(xpath, xmlDoc, null, XPathResult.ANY_TYPE,null);
|
Select titles from all book Nodes
The following path syntax selects all the title nodes:
Try it yourself.
Select the title of the first book Node
The following path syntax selects only the title of the first book node under the bookstore
element:
Try it yourself
There is a problem with this. The example above shows different results in IE
and other browsers.
IE5 and later has implemented that [0] should be the first node,
but according to the W3C standard it should have been [1]!!
A Workaround!
To solve the [0] and [1] problem in IE5+, you can set the SelectionLanguage
to XPath.
The following path syntax selects only the title of the first book node under the bookstore
element:
xml.setProperty("SelectionLanguage","XPath");
xml.selectNodes("/bookstore/book[1]/title");
|
Try it yourself
Select the prices
The following path syntax selects the text from all the price nodes:
/bookstore/book/price/text()
|
Try it yourself.
Selecting price Nodes with Price>35
The following path syntax selects all the price nodes with a price higher than
35:
/bookstore/book[price>35]/price
|
Try it yourself.
Selecting title Nodes with Price>35
The following path syntax selects all the title nodes with a price higher
than 35:
/bookstore/book[price>35]/title
|
Try it yourself.
The Altova MissionKit is a suite of intelligent XML tools, including:
XMLSpy® – industry-leading XML editor
- Support for all XML-based technologies
- Graphical editing views, powerful debuggers, code generation, & more
MapForce® – graphical data mapping tool
- Drag-and-drop data conversion with code generation
- Support for XML, DBs, EDI, Excel® 2007, text, Web services
StyleVision® – visual stylesheet designer
- Drag-and-drop stylesheet design for XML & databases
- Output to HTML, PDF, RTF, Word 2007, & more
And more…
Try before you buy with a free fully functional 30-day trial
Download today
|
|
Get Your Diploma!
W3Schools' Online Certification Program is the perfect solution for busy
professionals who need to balance work, family, and career building.
The HTML Certificate is for developers who want to document their knowledge of HTML, XHTML, and CSS.
The JavaScript Certificate is for developers who want to document their knowledge of JavaScript and the HTML DOM.
The XML Certificate is for developers who want to document their knowledge of XML, XML DOM and XSLT.
The ASP Certificate is for developers who want to document their knowledge of ASP, SQL, and ADO.
The PHP Certificate is for developers who want to document their knowledge of PHP and SQL (MySQL).
|
|