AJAX - The Complete Reference

PART IV

Appendix A: JavaScript Quick Reference 553

Language

Version

ECMA

Conformance Browser Versions Notes

JavaScript 1.0 Very Loose

ECMA-262 Edition 1

Netscape 2 Numerous implementation problems,

especially with the Date object. Lacks

some operators (===) and statements

(switch) commonly used. Simple object

model (forms, window, and links).

JavaScript 1.1 Loose ECMA-262

Edition 1

Netscape 3 Loose conformance to ECMA-262

Edition 1. Extended simple object

model adding image, applet, and plug-

in access.

JavaScript 1.2 Loose ECMA-262

Edition 1

Netscape 4.0–4.05 DHTML generation features such

as Layer object and JSSS features

introduced.

JavaScript 1.3 ECMA-262 Edition 1 Netscape 4.06–4.7 Strict conformance to ECMA-262

Edition 1. Layer object and JSSS

features continue to be supported.

JavaScript 1.5 ECMA-262 Edition 3 Firefox 1.x DHTML generation features removed

in favor of standard DOM. Native XHRs

introduced.

JavaScript 1.6 ECMA-262 Edition

3 with E4X related

enhancements

Firefox 1.5x Array extensions like map, for each,

every, some, array and string generics,

XML handling features.

JavaScript 1.7 ECMA-262 Edition

3 with E4X related

enhancements

Firefox 2.x Python-like generators, array

comprehensions, let statement

and block scope, destructuring

assignments.

JavaScript 1.8 ECMA-262 Edition

3 with E4X related

enhancements

Firefox 3.0 Modifications to the Python style

of generators, a simplified form of

anonymous functions, reduce()

and reduceRight() methods for

array. JSON-native support to be

potentially added ahead of JavaScript

2.0. General movement toward 2.0

release.

JavaScript 2.0 ECMA-262 Edition

4 + E4X (TBD)

TBD New standard still unfinished at the

time of this writing. Likely to include

features such as optional static

typing, packages and namespaces,

generators and iterators, JSON, and

class-based OOP.

TABLE A-2 Netscape/Mozilla/Firefox JavaScript Version History