ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Working with XML
Document A single XML structure. An XML document can contain any number of elements (or can consist only of a
single empty element); however, an XML document must have a single top-level element that contains all the other
elements in the document.
Node Another name for an XML element.
Attribute A named value associated with an element that is written into the opening tag of the element in
attributename="value" format, rather than being written as a separate child element nested inside the element.
The E4X approach to XML processing
Flash Player 9 and later, Adobe AIR 1.0 and later
The ECMAScript for XML specification defines a set of classes and functionality for working with XML data. These
classes and functionality are known collectively as E4X. ActionScript 3.0 includes the following E4X classes: XML,
XMLList, QName, and Namespace.
The methods, properties, and operators of the E4X classes are designed with the following goals:
Simplicity—Where possible, E4X makes it easier to write and understand code for working with XML data.
Consistency—The methods and reasoning behind E4X are internally consistent and consistent with other parts of
ActionScript.
Familiarity—You manipulate XML data with well-known operators, such as the dot (.) operator.
Note: There is a different XML class in ActionScript 2.0. In ActionScript 3.0 that class has been renamed as
XMLDocument, so that the name does not conflict with the ActionScript 3.0 XML class that is part of E4X. In
ActionScript 3.0, the legacy classes—XMLDocument, XMLNode, XMLParser, and XMLTag—are included in the
flash.xml package primarily for legacy support. The new E4X classes are core classes; you need not import a package to
use them. For details on the legacy ActionScript 2.0 XML classes, see the flash.xml packagein the ActionScript 3.0
Reference for the Adobe Flash Platform.
Here is an example of manipulating data with E4X:
var myXML:XML =
burger
3.95
fries
1.45
Often, your application will load XML data from an external source, such as a web service or a RSS feed. However, for
clarity, the code examples provided here assign XML data as literals.
As the following code shows, E4X includes some intuitive operators, such as the dot (.) and attribute identifier (@)
operators, for accessing properties and attributes in the XML:
trace(myXML.item[0].menuName); // Output: burger
trace(myXML.item.(@id==2).menuName); // Output: fries
trace(myXML.item.(menuName=="burger").price); // Output: 3.95
Last updated 6/6/2012
98