ECMAScript for XML (E4X) is a programming language extension that adds native XML support to ECMAScript (which include ActionScript, DMDScript, JavaScript, JScript). It does this by providing access to the XML document in a form that mimics XML syntax. The goal is to provide an alternative to DOM interfaces that uses a simpler syntax for accessing XML documents. It also offers a new way of making XML visible. Before the release of E4X, XML was always accessed at an object level. E4X instead treats XML as a primitive (like characters, integers, and booleans). This implies faster access, better support, and acceptance as a building block (data structure) of a program. The Extensible Markup Language (XML) is a general-purpose markup language. ... ECMAScript is a scripting programming language, standardized by Ecma International in the ECMA-262 specification. ... ActionScript is a scripting language based on ECMAScript, used primarily for the development of websites and software using the Adobe Flash Player platform (in the form of SWF files embedded into Web pages). ... The DMDScript programming language is Digital Mars implementation of the ECMAScript engine, and thus, scripting language. ... JavaScript is a scripting language most often used for client-side web development. ... JScript is a computer programming language created by Microsoft and is a superset of the ECMAScript programming language, which is known most commonly as JavaScript. ... // Document Object Model (DOM) is a platform- and language-independent standard object model for representing HTML or XML and related formats. ... In computer science, primitive types, as distinct from composite types - are datatypes provided by a programming language as basic building blocks. ...

E4X is standardized by Ecma International in the ECMA-357 standard. The first edition was published in June 2004, the second edition in December 2005. Ecma International is an international membership-based standards organization for information and communication systems. ...

 var sales = <sales vendor="John"> <item type="peas" price="4" quantity="5"/> <item type="carrot" price="3" quantity="10"/> <item type="chips" price="5" quantity="3"/> </sales>; alert( sales.item.(@type == "carrot").@quantity ); alert( sales.@vendor ); for each( var price in sales..@price ) { alert( price ); } 

Implementations

The first implementation of E4X was designed by Terry Lucas and John Schneider and appeared in BEA's Weblogic Workshop 7.0 released in Feburary 2002. BEA's implementation was based on Rhino and released before the ECMAScript E4X spec was completed in June 2004. John Schneider wrote an article on the XML extensions in BEA's Workshop at the time. The reference documentation for this pre-E4X language is still available. BEA Systems, Inc. ... Rhino is an open source JavaScript engine. ...

E4X is implemented in SpiderMonkey (Gecko's JavaScript engine) and in Rhino (Mozilla's other JavaScript engine written in Java instead of C). SpiderMonkey is the code name for the first ever JavaScript engine, written by Brendan Eich at Netscape Communications and later released as open source. ... Epiphany using Gecko to render the Wikipedia main page Gecko is the open source, free software web browser layout engine used in all Mozilla-branded software and its derivatives, including later Netscape releases. ... Rhino is an open source JavaScript engine. ...

As Mozilla Firefox is based on Gecko, it can be used to run scripts using E4X. The specification is supported in the 1.5 release or later. Mozilla Firefox is a graphical web browser developed by the Mozilla Corporation and a large community of external contributors. ... Epiphany using Gecko to render the Wikipedia main page Gecko is the open source, free software web browser layout engine used in all Mozilla-branded software and its derivatives, including later Netscape releases. ...

Note: To correctly run a script using Firefox 1.5 "; e4x=1" must be appended to the end of the script type attribute (e.g. <script type="text/javascript; e4x=1">).

Adobe's ActionScript 3 scripting language fully supports E4X. Early previews of ActionScript 3 were first made available in late 2005. Adobe officially released the language with Flash Player 9 on June 28, 2006. ActionScript is a scripting language based on ECMAScript, used primarily for the development of websites and software using the Adobe Flash Player platform (in the form of SWF files embedded into Web pages). ... ActionScript is a scripting language based on ECMAScript, used primarily for the development of websites and software using the Adobe Flash Player platform (in the form of SWF files embedded into Web pages). ...

E4X is also available in Adobe AIR and Adobe Flex as both products use ActionScript 3 as a scripting language. Adobe Integrated Runtime (AIR), codenamed and originally named Apollo[1], is a cross-OS runtime environment for building Rich Internet Applications, using Flash, Flex, HTML, Ajax, that can be deployed as a desktop application. ... Adobe Flex is an umbrella term for a group of technologies initially released in March of 2004 by Macromedia to support the development and deployment of rich Internet applications based on their proprietary Macromedia Flash platform. ...

Resources

• Tutorial from W3 Schools
• ECMA-357 standard
• E4X at faqts.com
• Slides from 2005 E4X Presentation by Brendan Eich, Mozilla Chief Architect
• E4X At Mozilla Developer Center