- Language resources
- 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 or ES6) 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.
- Version shipped in Netscape Navigator 3.0. Released on August 19, 1996.
- Version shipped in Netscape Navigator 4.0-4.05. Released on June 11, 1997.
- 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.
- 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.
- Version shipped in Firefox 1.5. Released in November 2005.
Includes ECMAScript for XML (E4X), new
- Version shipped in Firefox 2. Released in October 2006.
Includes generators, iterators, array comprehensions,
letexpressions, and destructuring assignment.
- Version shipped in Firefox 3. Released in June 2008.
Includes expression closures, generator expressions and
- Version shipped in Firefox 3.5. Released on June 30, 2009.
Includes the TraceMonkey JIT and supports native JSON.
- Version shipped in Firefox 3.6. Released June 22, 2009.
Includes only minor changes.
- Version shipped in Firefox 4. Released July 27, 2010.
Includes many new features for ECMA-262 Edition 5 compliance.