ECMAScript is a scripting programming language, standardized by Ecma International in the ECMA-262 specification. The language is widely used on the web, and is often referred to as JavaScript or JScript, although those two languages are extensions of the ECMA-262 standard. A programming paradigm is a paradigmatic style of programming (compare with a methodology, which is a paradigmatic style of doing software engineering). ... A multiparadigm programming language is a programming language that supports more than one programming paradigm. ... 1997 (MCMXCVII) was a common year starting on Wednesday of the Gregorian calendar. ... Brendan Eich is a computer programmer. ... Ecma International is an international membership-based standards organisation for information and communication systems. ... In computer science, a type system defines how a programming language classifies values and expressions into types, how it can manipulate those types and how they interact. ... In computer science, duck typing is a term for dynamic typing typical of some programming languages, such as Smalltalk or Visual FoxPro, where a variables value itself determines what the variable can do. ... In computing, weak typing, when applied to a programming language, is used to describe how the language handles datatypes. ... On computer science, a datatype (often simply type) is a name or label for a set of values and some operations which can be performed on that set of values. ... JavaScript is the name of Netscape Communications Corporations implementation of the ECMAScript standard, a scripting language based on the concept of prototype-based programming. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... JScript is Microsofts Active Scripting implementation of ECMAScript. ... JScript . ... The DMDScript programming language is Digital Mars implementation of the ECMAScript engine, and thus, scripting language. ... InScript is a closed-source library providing an ECMAScript engine for ECMA-262 3ed, written in C++ (and some Java classes for LiveConnect). ... This article or section does not cite its references or sources. ... Perl, also Practical Extraction and Report Language (a backronym, see below) is a dynamic procedural programming language designed by Larry Wall and first released in 1987. ... Scripting languages (commonly called scripting programming languages or script languages) are computer programming languages created to shorten the traditional edit-compile-link-run process. ... A programming language is an artificial language that can be used to control the behavior of a machine, particularly a computer. ... Ecma International is an international membership-based standards organisation for information and communication systems. ... The Web and WWW redirect here. ... JavaScript is the name of Netscape Communications Corporations implementation of the ECMAScript standard, a scripting language based on the concept of prototype-based programming. ... JScript is Microsofts Active Scripting implementation of ECMAScript. ...

History

In December 1995 Sun Microsystems and Netscape Communications Corporation introduced [1] JavaScript. In March 1996 Netscape Communications Corporation released Netscape Navigator 2.0, which featured support for JavaScript. Due to the de facto success of JavaScript as a client-side scripting language for web pages, Microsoft developed a "roughly" compatible language known as JScript, which was included in Internet Explorer 3.0, released in August 1996. Sun Microsystems, Inc. ... Netscape Communications Corporation was the publisher of the Netscape Navigator web browser as well as many other internet and intranet client and server software products. ... JavaScript is the name of Netscape Communications Corporations implementation of the ECMAScript standard, a scripting language based on the concept of prototype-based programming. ... Netscape Navigator, also known as Netscape, was a proprietary web browser that was popular during the 1990s. ... Microsoft Corporation, (NASDAQ: MSFT, HKSE: 4338) is a multinational computer technology corporation with global annual revenue of US$44. ... Windows Internet Explorer, previously Internet Explorer, abbreviated IE, or MSIE[1], is a graphical web browser developed by Microsoft and included as part of the Microsoft Windows line of operating systems. ...

Netscape submitted the JavaScript specification to Ecma International for standardization; the work on the specification, ECMA-262, began in November 1996. The first edition of ECMA-262 was adopted by the ECMA General Assembly of June 1997. Ecma International is an international membership-based standards organisation for information and communication systems. ...

ECMAScript is the name of the scripting language standardized in ECMA-262. Both JavaScript and JScript technologies aim to be compatible with ECMAScript, while providing additional features not described in the ECMA specification.

Versions

There are three editions of ECMA-262 published, and the work on the fourth edition is in progress.

In June 2004 Ecma International published ECMA-357 standard, defining an extension to ECMAScript, known as E4X (ECMAScript for XML). ECMAScript for XML (E4X) is a programming language extension that adds native XML support to ECMAScript (ActionScript, DMDScript, E4X, JavaScript, JScript). ...

Dialects

ECMAScript is supported in many applications, especially web browsers, where it's commonly called JavaScript. Dialects typically include their own, different standard libraries, of which some are standardized separately – such as the W3C-specified DOM. Some implementations, such as ActionScript used in Flash, have a completely different set of libraries. This means that applications written in one dialect of ECMAScript will not likely work in another, unless they are designed to be compatible. An example of a web browser (Mozilla Firefox running under Microsoft Windows). ... In C++, the Standard Library is a collection of classes and functions, which are written in the core language. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Document Object Model (DOM) is a description of how an HTML or XML document is represented in a tree structure. ...

Note (1): Gecko 1.8.1 has partial support of E4X [2] and a few other features, see New in JavaScript 1.7. Adobe Acrobat was the first software to support Adobe Systems Portable Document Format (PDF). ... JavaScript is the name of Netscape Communications Corporations implementation of the ECMAScript standard, a scripting language based on the concept of prototype-based programming. ... The DMDScript programming language is Digital Mars implementation of the ECMAScript engine, and thus, scripting language. ... OpenLaszlo is an open source platform for the development and delivery of web applications with a usable human interface (sometimes called Rich Internet Applications) on the World Wide Web. ... JavaScript is the name of Netscape Communications Corporations implementation of the ECMAScript standard, a scripting language based on the concept of prototype-based programming. ... iCab is a highly-configurable web browser for the Macintosh by iCab Company. ... InScript is a closed-source library providing an ECMAScript engine for ECMA-262 3ed, written in C++ (and some Java classes for LiveConnect). ... The Extensible Markup Language (XML) is a W3C-recommended general-purpose markup language that supports a wide variety of applications. ... ECMAScript for XML (E4X) is a programming language extension that adds native XML support to ECMAScript (ActionScript, DMDScript, E4X, JavaScript, JScript). ... ECMAScript for XML (E4X) is a programming language extension that adds native XML support to ECMAScript (ActionScript, DMDScript, E4X, JavaScript, JScript). ...

Note (2): Microsoft claims that JScript 8.0 supports "almost all of the features of the ECMAScript Edition 3 Language Specification" but does not list the unsupported features.

Note (3): In addition to supporting ECMA-262 edition 3, ActionScript 2 also included support of properties, methods, and mechanisms that were proposed in early draft specifications of as yet unseen versions of ECMAScript. It remains to be seen if ActionScript will stay in sync with future changes to the ECMAScript specifications.

Note (4): As claimed by Adobe, it implements the preliminary edition 4 of ECMA-262 [3]

Note (5): As stated by OpenLaszlo, it partially implements edition 3 of ECMA-262 [4]

The Mozilla implementations, (SpiderMonkey in the C programming language and Rhino in the Java programming language), are used in several third-party programs, including Konfabulator and the Macintosh system-level scripting language JavaScript OSA. SpiderMonkey is the code name for the first ever JavaScript engine, written by Brendan Eich at Netscape Communications and later released as open source. ... Wikibooks has a book on the topic of C Programming The C programming language (often, just C) is a general-purpose, procedural, imperative computer programming language developed in the early 1970s by Dennis Ritchie for use on the Unix operating system. ... Rhino is an open source JavaScript engine. ... Java is an object-oriented programming language developed by James Gosling and colleagues at Sun Microsystems in the early 1990s. ... Third party is a term used in several contexts, including: Third party (politics) Third-party manufacturers: See aftermarket. ... Screenshot of Konfabulator Screenshot of Konfabulator for Windows with Konsposé enabled. ... JavaScript OSA, (originally JavaScript for OSA, abbreviated as JSOSA), is a freeware inter-process communication scripting language for the Macintosh computer. ...

Apple's Safari uses JavaScriptCore which is based on the KDE KJS library. Apple Computer, Inc. ... Safari is a web browser developed by Apple Computer, Inc. ... JavaScriptCore is a framework developed by Apple that provides a JavaScript engine for Mac OS X. It, along with WebCore, make up WebKit. ... KDE (K Desktop Environment) (IPA: ) is a free desktop environment and development platform built with Trolltechs Qt toolkit. ... KJS is KDEs JavaScript engine that was originally developed for the KDE projects Konqueror web browser by Harri Porten in 2000. ...

Version correspondence

The following table is based on [5] and [6]; items on the same line are approximately the same language.

Mozilla is a computer term which has had many different uses, though all of them have been related to the now-defunct Netscape Communications Corporation and its related application software. ... ECMAScript for XML (E4X) is a programming language extension that adds native XML support to ECMAScript (ActionScript, DMDScript, E4X, JavaScript, JScript). ... Python is an interpreted programming language created by Guido van Rossum in 1990. ... List comprehension is a programming language construct for list processing, analogous to the set-builder notation (set comprehension), that is, the mathematical notation such as the following: For an example, in Haskells list comprehension syntax, the example set-builder construct above would be written as: S = [ x | x<-[0. ... In computer programming in general, a scope is an enclosing context. ... JScript . ... ASP.NET is a set of web application development technologies marketed by Microsoft. ...

Fourth edition

The current work on the fourth edition of ECMAScript has received some criticism, as there is thought to be a concerted effort by the organization to change the language from a prototype-based programming language into a more traditional class-based programming one, in essence, changing the very nature of how JavaScript treats relationships between objects. JavaScript is often championed by prototype-based language advocates, as it is the best known language with this object-oriented feature. ActionScript version 2.0 is an example of a ECMAScript implementation which is already more class-based than prototype-based. It will be formally defined in terms of Standard ML of New Jersey, a member of the ML programming language family[9]; ML offers strong support for many desired or proposed features such as tail recursion.[10] Prototype-based programming is a style of object-oriented programming in which classes are not present, and behaviour reuse (known as inheritance in class-based languages) is accomplished through a process of cloning existing objects which serve as prototypes. ... Class-based programming, or more commonly class-orientation, refers to the style of object-oriented programming in which inheritance is achieved by defining classes of objects, as opposed to the objects themselves (compare Prototype-based programming). ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Standard ML of New Jersey (abbreviated SML/NJ) is a compiler and programming environment for Standard ML. Aside from its runtime system, which is written in C, SML/NJ is written in Standard ML. It was developed jointly by Bell Laboratories and Princeton University. ... ML is a general-purpose functional programming language developed by Robin Milner and others in the late 1970s at Edinburgh University, whose syntax is inspired by ISWIM. Historically, ML stands for metalanguage as it was conceived to develop proof tactics in the LCF theorem prover (the language of which ML... In computer science, tail recursion is a special case of recursion that can be easily transformed into an iteration. ...

It is also noted that the fourth edition has been very long awaited. The third edition was released in 1999, since that time, interactive web applications have grown tremendously in complexity, while the scripting language has remained essentially frozen.

ECMAScript variables

Variables in ECMAScript are defined by using the var operator (short for variable), followed by the variable name, such as:

 var test = "hi"; 

In this example, the variable test is declared and given an initialization value of "hi" (a string). Because ECMAScript is dynamically typed, the interpreter automatically creates a string value for test without any explicit type declaration. You can also define two or more variables using the same var statement:

 var test = "hi", test2 = "hola"; 

The previous code defines the variable test to have a value of "hi" and the variable test2 to have a value of "hola". Variables using the same var statement don’t have to be of the same type, however, as shown in the following:

 var test = "hi", age = 25; 

This example defines test (yet again) in addition to another variable named age that is set to the value of 25. Even though test and age are two different data types, this is perfectly legal in ECMAScript. Unlike Java, variables in ECMAScript do not require initialization (they are actually initialized behind the scene). Therefore, this line of code is valid:

 var test; 

Also unlike Java, variables can hold different types of values at different times; this is the advantage of loosely typed variables. A variable can be initialized with a string value, for instance, and later on be set to a number value, like this:

 var test = 'hi'; alert(test); //outputs 'hi' //do something else here test = 55; alert(test); //outputs '55' 

This code outputs both the string and the number values without incident (or error). As mentioned previously, it is best coding practice for a variable to always contain a value of the same type throughout its use.

See also

• List of ECMAScript engines
• Document Object Model

The following is a list of ECMAScript engines. ... Document Object Model (DOM) is a description of how an HTML or XML document is represented in a tree structure. ...

External links

• Standard ECMA-262 ECMAScript Language Specification 3rd edition (December 1999)
• Standard ECMA-290 ECMAScript Components Specification (June 1999)
• Standard ECMA-327 ECMAScript 3rd Edition Compact Profile (June 2001)
• Standard ECMA-357 ECMAScript for XML (E4X) Specification (June 2004)
• Export Root of the ECMAScript 4 Committee Wiki