XPath Examples
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In this section, let's learn some basic XPath syntax through examples.
XML Example Document
We will use this XML document in the following examples:
"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>
Load XML document
All modern browsers support the method of loading XML documents using XMLHttpRequest.
Code for most modern browsers:
var xmlhttp=new XMLHttpRequest()
Code for old Microsoft browsers (IE 5 and 6):
var xmlhttp=new ActiveXObject("Microsoft.XMLHTTP")
Select nodes
Unfortunately, Internet Explorer and other processors handle XPath differently.
In our example, we include code that is applicable to most mainstream browsers.
Internet Explorer uses the selectNodes() method to select nodes from an XML document:
xmlDoc.selectNodes(xpath);
Firefox, Chrome, Opera, and Safari use the evaluate() method to select nodes from an XML document:
xmlDoc.evaluate(xpath, xmlDoc, null, XPathResult.ANY_TYPE,null);
Select all titles
The following example selects all title nodes:
/bookstore/book/title
Select the title of the first book
The following example selects the title of the first book node under the bookstore element:
/bookstore/book[1]/title
There is a problem here. The example above produces different results in IE and other browsers.
IE5 and later versions treat [0] as the first node, while according to W3C standards, it should be [1].
To solve the problem of [0] and [1] in IE5+, a language selection (SelectionLanguage) can be set for XPath.
The following example selects the title of the first book node under the bookstore element:
xml.setProperty("SelectionLanguage","XPath"); xml.selectNodes("/bookstore/book[1]/title");
Select all prices
The following example selects all text within the price nodes:
/bookstore/book/price/text()
Select nodes with a price greater than 35
The following example selects all price nodes with a price greater than 35:
/bookstore/book[price>35]/price
Select title nodes with a price greater than 35
The following example selects all title nodes with a price greater than 35:
/bookstore/book[price>35]/title
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