* v * t * e
ECMASCRIPT (or ES) is a trademarked scripting-language
specification standardized by
Ecma International in ECMA-262 and
ISO/IEC 16262. It was created to standardize
* 1 History
* 2 Features * 3 Syntax * 4 Implementations * 5 Version correspondence * 6 Conformance tests * 7 See also * 8 References * 9 External links
ECMAScript specification is a standardized specification of a
scripting language developed by
Brendan Eich of Netscape ; initially
Owing to the widespread success of
There are seven editions of ECMA-262 published. Work on version 7 of the standard, was finalized in June 2016.
EDITION DATE PUBLISHED CHANGES FROM PRIOR EDITION EDITOR
1 June 1997 First edition Guy L. Steele Jr.
2 June 1998 Editorial changes to keep the specification fully aligned with ISO/IEC 16262 international standard Mike Cowlishaw
3 December 1999 Added regular expressions , better string handling, new control statements, try/catch exception handling, tighter definition of errors, formatting for numeric output and other enhancements Mike Cowlishaw
4 Abandoned Fourth Edition was abandoned, due to political differences concerning language complexity. Many features proposed for the Fourth Edition have been completely dropped; some are proposed for ECMAScript Harmony.
Adds "strict mode," a subset intended to provide more thorough
error checking and avoid error-prone constructs. Clarifies many
ambiguities in the 3rd edition specification, and accommodates
behaviour of real-world implementations that differed consistently
from that specification. Adds some new features, such as getters and
setters, library support for
5.1 June 2011 This edition 5.1 of the ECMAScript Standard is fully aligned with third edition of the international standard ISO/IEC 16262:2011. Pratap Lakshman, Allen Wirfs-Brock
6 June 2015 The Sixth Edition, initially known as ECMAScript 6 (ES6) and later renamed to ECMAScript 2015 (ES2015) adds significant new syntax for writing complex applications, including classes and modules, but defines them semantically in the same terms as ECMAScript 5 strict mode. Other new features include iterators and for/of loops, Python -style generators and generator expressions, arrow functions, binary data, typed arrays, collections (maps, sets and weak maps), promises , number and math enhancements, reflection, and proxies (metaprogramming for virtual objects and wrappers). As the first " ECMAScript Harmony" specification, it is also known as "ES6 Harmony." Allen Wirfs-Brock
7 June 2016 The Seventh Edition, also known as ECMAScript 2016, intended to continue the themes of language reform, code isolation, control of effects and library/tool enabling from ES2015, includes two new features: the exponentiation operator (**) and Array.prototype.includes. Brian Terlson
8 June 2017 New features proposed include concurrency and atomics, zero-copy binary data transfer, more number and math enhancements, syntactic integration with promises (await/async), observable streams, SIMD types, better metaprogramming with classes, class and instance properties, operator overloading, value types (first-class primitive-like objects), records and tuples, and traits.
In June 2004, Ecma International published ECMA-357 standard, defining an extension to ECMAScript, known as ECMAScript for XML (E4X). Ecma also defined a "Compact Profile" for ECMAScript – known as ES-CP, or ECMA 327 – that was designed for resource-constrained devices, which was withdrawn in 2015.
4TH EDITION (ABANDONED)
The proposed fourth edition of ECMA-262 (ECMASCRIPT 4 or ES4) would have been the first major update to ECMAScript since the third edition was published in 1999. The specification (along with a reference implementation) was originally targeted for completion by October 2008. An overview of the language was released by the working group on October 23, 2007.
* classes , * a module system , * optional type annotations and static typing , probably using a structural type system , * generators and iterators , * destructuring assignment , and * algebraic data types .
The intent of these features was partly to better support programming
in the large , and to allow sacrificing some of the script's ability
to be dynamic to improve performance. For example, Tamarin – the
virtual machine for
In addition to introducing new features, some ES3 bugs were proposed
to be fixed in edition 4. These fixes and others, and support for
Work started on Edition 4 after the ES-CP (Compact Profile)
specification was completed, and continued for approximately 18 months
where slow progress was made balancing the theory of Netscape's
Yahoo, Microsoft, Google, and other 4th edition dissenters formed their own subcommittee to design a less ambitious update of ECMAScript 3, tentatively named ECMAScript 3.1. This edition would focus on security and library updates with a large emphasis on compatibility. After the aforementioned public sparring, the ECMAScript 3.1 and ECMAScript 4 teams agreed on a compromise: the two editions would be worked on, in parallel, with coordination between the teams to ensure that ECMAScript 3.1 remains a strict subset of ECMAScript 4 in both semantics and syntax.
However, the differing philosophies in each team resulted in repeated breakages of the subset rule, and it remained doubtful that the ECMAScript 4 dissenters would ever support or implement ECMAScript 4 in the future. After over a year since the disagreement over the future of ECMAScript within the Ecma Technical Committee 39, the two teams reached a new compromise in July 2008: Brendan Eich announced that Ecma TC39 would focus work on the ECMAScript 3.1 (later renamed to ECMAScript, 5th Edition) project with full collaboration of all parties, and vendors would target at least two interoperable implementations by early 2009. In April 2009, Ecma TC39 published the "final" draft of the 5th edition and announced that testing of interoperable implementations was expected to be completed by mid-July. On December 3, 2009, ECMA-262 5th edition was published.
6TH EDITION - ECMASCRIPT 2015
The 6th edition, officially known as ECMAScript 2015, was finalized in June 2015. This update adds significant new syntax for writing complex applications, including classes and modules, but defines them semantically in the same terms as ECMAScript 5 strict mode. Other new features include iterators and for/of loops, Python -style generators and generator expressions, arrow functions, binary data, typed arrays, collections (maps, sets and weak maps), promises , number and math enhancements, reflection, and proxies (metaprogramming for virtual objects and wrappers). The complete list is extensive.
Browser support for ES2015 is still incomplete. However, ES2015 code
can be transpiled into ES5 code, which has more consistent support
across browsers. Transpiling adds an extra step to build processes
whereas polyfills allow adding extra functionalities by including
7TH EDITION - ECMASCRIPT 2016
The 7th edition, officially known as ECMAScript 2016, was finalized in June 2016. New features include the exponentiation operator (**), Array.prototype.includes (not to be confused with ClassList.contains).
8TH EDITION - ECMASCRIPT 2017
The 8th edition, officially known as ECMAScript 2017, was finalized in June 2017. Includes await /async, which works using generators and promises.
ES.Next is a dynamic name that refers to whatever the next version is at time of writing. ES.Next features are more correctly called proposals, because, by definition, the specification has not been finalized yet.
THIS SECTION NEEDS EXPANSION. You can help by adding to it . (February 2017)
The ECMAScript language includes structured , dynamic , functional , and prototype-based features.
THIS SECTION IS EMPTY. You can help by adding to it . (February 2017)
Main article: ECMAScript syntax
Main article: List of ECMAScript engines
ECMAScript is supported in many applications, especially Web browsers
Explorer, JScript. Implementations sometimes include extensions to the
language, or to the standard library and related application
programming interfaces (API) such as the
World Wide Web
IMPLEMENTATION APPLICATIONS ECMASCRIPT EDITION
JerryScript Resource constrained IoT devices, Pebble 5.1
Nashorn Java 9 6
Nashorn Java 5.1
Rhino Java Platform, Standard Edition 3
Carakan (deprecated) Opera 12 5.1
Ejscript Appweb Web Server, Samba 4 2015
InScript iCab 3
Max/MSP engine Max 3
Adobe Acrobat X uses the
* ^ According to the widely used compatibility table, Firefox
supports the vast majority, but not all, of the features introduced in
ECMAScript 2015. See Tracking bug for
ECMAScript 6 in
* ^ According to the widely used compatibility table, Chrome
supports the vast majority, but not all, of the features introduced in
Items on the same line are approximately the same language.
1.0 (Netscape 2.0, March 1996) 1.0 (IE 3.0 – early versions, August 1996)
1.1 (Netscape 3.0, August 1996) 2.0 (IE 3.0 – later versions, January 1997)
1.2 (Netscape 4.0-4.05, June 1997)
1.3 (Netscape 4.06-4.7x, October 1998) 3.0 (IE 4.0, Oct 1997) Edition 1 (June 1997) / Edition 2 (June 1998)
1.4 (Netscape Server only) 4.0 (Visual Studio 6, no IE release)
5.0 (IE 5.0, March 1999)
5.1 (IE 5.01)
1.5 (Netscape 6.0, Nov 2000; also
later Netscape and
5.6 (IE 6.0, October 2001)
1.6 (Gecko 1.8,
1.7 (Gecko 1.8.1,
Edition 3 plus all
1.8 (Gecko 1.9,
Ecma International started developing a standards test for
Ecma 262 ECMAScript. Test262 is an
ECMAScript conformance test suite
that can be used to check how closely a
Development of test262 is a project of Ecma Technical Committee 39 (TC39). The testing framework and individual tests are created by member organizations of TC39 and contributed to Ecma for use in Test262.
Important contributions were made by Google (Sputnik testsuite) and
The following table shows current conformance results of browser products. Lower scores are better, although scores can not be compared, as tests are not weighted. Also, be aware that Test262 itself is likely to contain bugs that may impact a browser's score. So browsers with a score significantly lower than the current test suite bug count may not necessarily do better than those with a higher one. That may be particularly true when several browsers have a higher score in their current development builds as compared to their last released version.
Results of test262 (suite version: ES5, suite date: 2014-09-18) PRODUCT LATEST STABLE TEST262 FAILED PREVIEW/BETA TEST262 FAILED ALPHA TEST262 FAILED NIGHTLY TEST262 FAILED
ESR 38.4.0 7002228000000000000♠228/11552
Opera 33.0.1990.115 7002207000000000000♠207/11552 beta 34.0.2036.3 7002208000000000000♠208/11552 developer 35.0.2052.0 7002210000000000000♠210/11552
12.17 (classic) 7001110000000000000♠11/11552
Safari 7.1 (9537.85) 7000700000000000000♠7/11552
* ^ Stefanov, Stoyan (2010).
* ^ Krill, Paul (2008-06-23). "
* ^ "Version Information (JScript)". Msdn.microsoft.com. Archived from the original on 2009-12-17. Retrieved 2009-12-17. * ^ Andrew Clinick (July 14, 2000). "Introducing JScript .NET". Microsoft.com. Retrieved 2010-01-12. * ^ " ECMAScript Language – test262". Test262.ecmascript.org. Retrieved 2013-10-31. * ^ Schuster, Tom. "Bug 1453". ecmascript.org bug database. Retrieved 12 October 2014.
* Official website * The World of ECMAScript: John