Kangax’s ES5 compatibility table
Search WebKit bugs for "es5" and Good overview of WebKit progress
V8 bugs tagged "ES5", and search V8 bugs or Chromium bugs for “es5”.
The Besen ES5 project on sourceforge
ES5/3, an implementation of most of ES5/strict that runs on stock ES3 browsers.
See ES3.1 Proposal Working Draft, a proposal to TC39-TG1 on the Maintenance of the ECMAScript, 3rd Edition Specification.
— Pratap Lakshman 2007/04/15 01:43
See ES3.x Working Docs for various notes and documents related to maintenance and enhancement of ES 3
— Allen Wirfs-Brock 2007/11/06 16:26
The following relates to an earlier proposal. Discussion of it lead to the “ES3.1” concept and the above draft proposal.
— Allen Wirfs-Brock 2007/04/16 09:18
In my opinion this page needs a fresh start. Its entire current contents should move to the discussion page (at the top is fine) and a technically phrased proposal for subsetting ES4 to make an “ES3.1”, as discussed in minutes_mar_21_2007, should be made here.
— Brendan Eich 2007/03/22 15:46
A working draft of a new proposal is almost ready. Pratap will soon post it.
— Allen Wirfs-Brock 2007/04/13 13:59
(Also see the discussion page for this proposal).
The following is a proposal to Refocus TC39-TG1 on the Maintenance of the ECMAScript, 3rd Edition Specification
[I have extracted here the part of this proposal that does not require input from TC39. I recommend the other parts be taken up with that committee. — Jeff Dyer 2007/03/19 08:12]
In light on the broad adoption of ECMAScript, 3rd Edition for web browser based applications it is clear that this language will remain an important part of the world-wide-web infrastructure for the foreseeable future. However, since the publication of the ECMAScript, 3rd Edition specification in 1999 there has been feature drift between implementations and cross-implementation compatibility issues arising from deficiencies and ambiguities in the specification. The purpose of this work item is to create a maintenance revision of the specification (a 4th Edition) that focuses on these goals:
This work item should become the primary focus of TC39-TG1.
Our current set of proposed extensions to ES3 are aligned with this proposal. However, limiting our focus to incremental enhancements seems shortsighted in light of the way the web has changed and our experience with the proposed extensions to ES3 (in JScript.NET, ActionScript 3, and JavaScript 1.7, to name a few).
— Jeff Dyer 2007/03/19 08:40
I’m going to have to agree with Jeff, and would like to further object to the idea of creating a new language. Getting ES to run decently on limited-memory devices has always been a challenge. Trying to add another language is just not possible: there simply isn’t room. (Not that it would matter, because I don’t think this second language would go anywhere.)
— Chris Pine 2007/03/20 05:56
I’m sure that Chris meant “a new incompatible language”. Which is a point I’ve made repeatedly in response to arguments against backward compatibility. The learning and switching costs for developers, the code migration cost becoming a rewrite tax, and the unbearable costs to implementors such as Opera (and Mozilla – we can’t justify putting C-Python into Firefox, never mind a bigger incompatible language). ES4 has been designed with able and active representation from Opera all along, to fit on small devices and process ES3 (”Web JavaScript”) content with full backward compatibility at the cost of a few version checks.
— Brendan Eich 2007/03/20 17:20