The ECMAScript standard is documented in the ECMA-262 specification.
- Version shipped in Netscape Navigator 3.0.
- Version shipped in Netscape Navigator 4.0-4.05.
- Version shipped in Netscape Navigator 4.06-4.7x.
- Version shipped in Netscape Navigator 6.0 and Firefox 1.0. Standardization work to be compliant with ECMA-262 3rd Edition.
- Version shipped in Firefox 1.5.Includes ECMAScript for XML (E4X), new Array methods plus String and Array generics
- Version shipped in Firefox 2.Includes generators, iterators, array comprehensions, let expressions, and destructuring assignment.