[JavaScript] ECMAScript

ECMAScript is the scripting language standardized by ECMA (European Computer Manufacturers Association) International. Well-known dialects are JavaScript, JScript, and ActionScript.


1. JavaScript and ECMAScript

JavaScript is much more than a client-script language in web browsers. It can be hosted in many environments.

JavaScript was originally developed for Netscape and due to its success, MS developed its own dialect JScript. Netscape brought JavaScript to ECMA for standardization in 1996. The name “ECMAScript” was a compromise between Netscape and MS.

ECMAScript defines the core part of the language. But it is not host-dependent. It does not know anything about HTML or browsers.


2. Versions of ECMAScript

The first version is released in 1997.

  • Version 1 : 1997
  • Version 2 : 1998
  • Version 3 : 1999
  • Version 4 : Abandoned
  • Version 5 : 2009
  • Version 5.1 : 2011
  • Version 6 (ES6): 2015
  • Version 7: 2016
  • Version 8: 2017


3. ECMAScript3

The third version had been used widely until ECMAScript5 was released.

ECMA3 introduced the following features:

  • Regular expressions
  • Exception handling (try/catch)
  • Tighter definition of errors
  • Formatting for numeric output


4. ECMAScript5

The version 5 of ECMAScript adds

  • Strict mode
  • JSON” object : JSON.parse() / JSON.stringify()
  • Object” object : reflection methods are added
  • Getters and Setters


5. ECMAScript2015 (ES6)

This version was initially known as ES6 (still widely used) and later renamed to ECMAScript2015. This introduced significant syntax changes.

  • Classes and Modules
  • Iterators and for/of loops
  • Generators
  • Arrow functions
  • Collections (maps, sets and weak maps)
  • Promises
  • Spread operators


6. ECMAScript2016

  • Exponential Operator (**)
  • Array.prototype.includes


7. ECMAScript2017

  • await/async


8. Browser Support for ECMAScript

Please refer to the following sites




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