John Resig, creator of jQuery and an evangelist for Mozilla, which was one of the major forces behind ECMAScript 4, said in a blog post Aug.13, "First, you can forget a lot of what you learned about ECMAScript 4, previously. Many of the complicated concepts contained in the language have been tossed. Instead there is a considerable amount of effort going into making sure that new features will be easily duplicable through other means."
Doug Crockford, a Yahoo engineer and a member of the Ecma technical committee focusing on advancing ECMAScript, said in an Aug. 14 blog post:
"Some of the features that were in ES4 were reasonable, so a new project, called Harmony, is starting which will look at adapting the best of ES4 on top of ES3.1. The success of this project will depend on the ability of TC39 [the Ecma technical committee drafting the standard] to do a better job of managing the tradeoffs between innovation and stability, and adopting a discipline for managing complexity. Simplicity should be highly valued in a standard. Simplicity cannot be added. Instead, complexity must be removed."
Meanwhile, some have characterized the move toward Harmony as a loss of face for Adobe because ECMAScript 4 was to be based on Adobe's ActionScript 3. Yet, "The folks who have written it this way have gotten it wrong, not least of all because they haven't been sitting in the meetings and haven't seen how the resulting differences come from good faith disagreements, not simple strategic posturing," Russell said. "ES4 (as outlined last fall) wasn't Adobe's language, and there was no chance that ES3.1 would have ever been as tepid as many assumed Microsoft wanted it to be."
Indeed, Russell said ECMAScript 4 was not ActionScript 3. "Major changes to the semantics of Adobe's initial contribution ensured that any truly compliant ES4 implementation from Adobe would have required many concessions, including the inclusion of a client-side compiler," he said.