This chapter contains information about JavaScript's version history and implementation status for Mozilla/SpiderMonkey-based JavaScript applications, such as Firefox.
ECMAScript versions
- Language resources
- Learn more about the ECMAScript standards on which the JavaScript language is based on.
- ECMAScript 5 support
- Implementation status for the current standard ECMA-262 Edition 5.1 in Mozilla-based engines and products.
- ECMAScript 2015 support
- Implementation status for the draft ECMA-262 Edition 6 (ES2015) in Mozilla-based engines and products.
- ECMAScript Next support
- Implementation status for upcoming ECMA-262 features as per the yearly (ES2016/ES2017/ES2018/...) release schedule in Mozilla-based engines and products.
JavaScript versions
Deprecated ( ). The explicit versioning and opt-in of language features was Mozilla-specific and are in process of being removed. Firefox 4 was the last version which referred to a JavaScript version (1.8.5). With new ECMA standards, JavaScript language features are now often mentioned with their initial definition in ECMA-262 Editions such as ECMAScript 2015.
JavaScript was released as version 1.0 in March 1996 in Netscape Navigator 2.0 and Internet Explorer 2.0.
- JavaScript 1.1
- Version shipped in Netscape Navigator 3.0. Released on August 19, 1996.
- JavaScript 1.2
- Version shipped in Netscape Navigator 4.0-4.05. Released on June 11, 1997.
- JavaScript 1.3
- Version shipped in Netscape Navigator 4.06-4.7x. Released on October 19, 1998.
Standardization work to be compliant with ECMA-262 1st and 2nd Edition.
- JavaScript 1.4
- Version shipped with Netscape's server-side JavaScript. Released in 1999.
- JavaScript 1.5
- Version shipped in Netscape Navigator 6.0 and Firefox 1.0. Release on November 14, 2000.
Standardization work to be compliant with ECMA-262 3rd Edition.
- JavaScript 1.6
- Version shipped in Firefox 1.5. Released in November 2005.
Includes ECMAScript for XML (E4X), new Array methods plus String and Array generics.
- JavaScript 1.7
- Version shipped in Firefox 2. Released in October 2006.
Includes generators, iterators, array comprehensions, let expressions, and destructuring assignment.
- JavaScript 1.8
- Version shipped in Firefox 3. Released in June 2008.
Includes expression closures, generator expressions and Array.reduce()
- JavaScript 1.8.1
- Version shipped in Firefox 3.5. Released on June 30, 2009.
Includes the TraceMonkey JIT and supports native JSON.
- JavaScript 1.8.2
- Version shipped in Firefox 3.6. Released June 22, 2009.
Includes only minor changes.
- JavaScript 1.8.5
- Version shipped in Firefox 4. Released July 27, 2010.
Includes many new features for ECMA-262 Edition 5 compliance.
This is the last JavaScript version.