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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Although the XML object looks and behaves in a similar way to a regular JavaScript object, the two objects are not the same.

ECMAscript for XML more colloquially known as E4X has had comparatively limited success of adoption in the face of the power of JSON, I suspect partially because of a general ambivalence that the Ttutorial community has towards working with XML, but more so because there is comparatively little out there describing how best to take advantage of the features that E4X offers. However, in some cases, you may have multiple types of items being added to a given element. There is a basic question that needs to be answered when addressing new technology.

Since we know there’s only one tutoria, with id 3, we can cast it to an XML object without problems. The function eNode2dNode performs the conversion one way, converting an E4X object into the root node of its own DOM-based document, while dNode2eNode makes the conversion in the other direction: But i think i need more help.

By nbilyk – Posted on October 7th, Select all descendents children, grandchildren, etc. You can use another method, attributesto identify attributes contained in an object. A working knowledge of XML and Javascript is required.


E4X Tutorial

Return the processing instruction children of element with the specified name if omitted, all are returned. As you can see, the output shows that the song was added to the third element in the XMLList object and that it is the same as the output from the code shown in Listing And you can filter by artist, which is not an attribute, as in Listing The more complex the conditional filter sthe more the advantage shows up in favor of E4X.

He is the webmaster for XForms. With the appendChild method, you can add a node to the end of an existing object or element. Other than the rather annoying inability for an element to reference itself in a filter the part contained in an expression such as the following, shown in bold: Thus, it is necessary to run a quick regular expression to remove all of these: This is used to good effect in the internally defined selectFeed function.

If there is a choice within the filtering expression between a child element name or a variable, the child element name will take precedence, sometimes with unexpected results, as shown below: Flash has some good documentation on using E4X at: To change the value of an element or attribute, assign a new value to it, as in Listing For instance, consider an expanded phone book:.

E4X uses methods where DOM uses properties. In this example, one might expect that x would be empty, as the type attribute of the first phone element is not equal to the value of the “preferred” variable. E4X facilitates the use of XML’s structural components, thereby enhancing that flexibility significantly. The JavaScript scripting language is extremely simple and well organized.

For instance, suppose that you had an object version of the phone book and you wanted to create a table showing the names and numbers of each person in the book. In the simplest case, the parsing is handled behind the scenes:.


In this case, dot notation cannot be allowed, and an escaped syntax must be employed. Loading xml Before we begin parsing any xml, I’ll explain briefly how to load the xml. Given the increasing dominance of XML as a messaging and transport protocol on the server and between server and client, the use of LINQ does open up the notion that you can take advantage of the rich characteristics that XML has to offer without having to complexify your code with DOM manipulation.

URLLoader ; import flash. Kurt Cagle is an author, research analyst with Burton Group, technology evangelist, information architect, and software developer specializing in web technologies.

Introducing E4X

First things first, are you using NetKernel version 2. In the first method, you create the object, and then load it as in Listing 3. ttuorial

Escape names with “. The code sequence in Listing 15 illustrates a e4s that you can use to initialize the XMLList object. The answer seems to be in section ” Namespaces in E4X are something of a headache, for much the same reason that they are a headache in XML in general.

If no elements match, the result is an empty XML list, s4x checked for empty using “. This information is extracted from the ECMA specification [1]. There are two ways to iterate over this XMLList. To request just the artist’s name in the classical genre, enter the statement in Listing 9.