Learn to use ECMAScript (aka JavaScript) for XML (E4X), and discover of technical articles and tips, tutorials, standards, and IBM Redbooks. ECMAscript for XML (more colloquially known as E4X) has had comparatively limited success of adoption in the face of the power of JSON. E4X: ECMAScript for XML ECMAScript for XML, better known as E4X, is a standard extension[22] to JavaScript This section presents a quick tutorial on E4X.

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For a complex element one with childrentoString returns the XML syntax representation of the element.

Returns the descendant elements children, grandchildren, etc. The parent property of the copy will be set to null. The feed is referenced within the function, as well as displayNode and linkNode, which defines the display area for a selected entry’s content and a button for launching the original page in a second window.

When tutorila in other tag-based environments, it may create some unforeseen difficulties. Listing 20 manipulates the Dave Brubeck data, which contains two songs. If you have several branches within your XML and want to get all users over lbs, you can use the descendants property. To retrieve a list of all of the phone entries tutorkal a given exchange, the E4X thtorial would be given as:. Consider, for instance, the process of retrieving an XML-based Atom feed from my blog at http: The following expressions are invalid E4X because of reserved words or invalid name characters.

E4X Tutorial

In addition, the flexible and agile E4X technology is tailor-made for those increasingly important mobile applications. A child element can be accessed by name as a property of the parent.

Think of it like you’re doing a search for something and it’s giving you the results. E4X is an extension to JavaScript that is available to both Firefox and ActionScript developers that turns XML into a native data type on par with strings, arrays, objects, and regular expressions. The following shows how you can create a new phone book with a single entry: Perhaps one of the biggest benefit of using E4X stems from the fact that most database systems and consequently many web sites are now moving towards producing XML content natively, whereas relatively few are doing the same thing with JSON feeds which consequently need to be crafted by hand.


The for operator is extended to more easily traverse the properties of an object especially children of an XML object, or items in an XMLList.

For example, to retrieve all the data from the classical genre, enter a statement similar to Listing 8. Contribute your ideas for improving this document to mashup-user wso2. The name of the variable is separate from the name of the XML tutorual value. The prependChild method adds a node before a child node of the identified element. Admittedly, in this case it doesn’t make that much difference determining the feed is relatively simplebut from a security standpoint this provides a layer of protection on potentially sensitive information.

Rutorial toString method works a litle differently for E4X objects than it does for other JavaScript objects. To do this in object-based JavaScript requires that you create a list and populate it:. For other kinds of objects, the value of the object.

Flash E4X Tutorial

The goal here is to minimize the amount of processing of the feed as a DOM, so here that process is handled by using the http. Since we know there’s only one user with id 3, we can cast it to an XML object without problems. The economy that these qualities create leads to simplified coding, enhanced code revising, and shorter code deployment cycles. XMLList object use-case was very concise and helpful – many thanks!


Returns true for attributes, text nodes, or elements without child elements, otherwise false.

Flash E4X Tutorial

But instead, the value of the “preferred” element is used. Creating E4X Objects What about parsing and serializing? This filtering operator applies a condition to the data that then sifts tutroial the requested elements from a child node. It’s also possible to remove an item from an existing E4X object via the delete command.

It is not a DOM representation of XML, but rather is its own rutorial entity, something that has its own set of associated methods and operators and that is intended to making it easier to work with XML than using the sometimes cumbersome methods associated with DOM perhaps the closest analogy I can think of would be the comparison between modeling clay with your bare hands and modeling clay with a waldo while wearing a space suit.

This returns all XML nodes in the xml. E4X uses methods where DOM uses properties.

E4X: JavaScript on steroids

The rule to remember is that within a filter expression, names are assumed to be relative to the context XML. Thus, it is necessary to run a quick regular expression to remove all of these:. This quick start guide should not only give you the basics of E4X, but also point out some of the tricky cases that an intermediate user will likely encounter.

Event ; import flash. Javascript has a fair number of reserved words that appear fairly commonly as XML element names.