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New Standard for JavaScript After Years of Disagreement

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After ten years with no major revision, the European Computer Manufacturers Association (ECMA) general assembly recently approved the ECMA-262 5th edition (ES5) spec as the ECMAScript standard.  JavaScript, JScript, and ActionScript are the well-known dialects of ECMAScript.  

The spec passed by a vote of 19 to 2, receiving less criticism than the unstandardized 4th edition.  Only IBM and Intel voted against the proposal.  IBM voted against the spec because of the lack of decimal and Intel didn't have enough time to look over the intellectual property implications.  The next step for the ECMA will be to submit the ES5 spec to the International Organization for Standardization (ISO).

The new standard now includes JavaScript Object Notation (JSON) as a component of ECMAScript.  Objects in the new ECMAScript can be shielded from manipulation with Object.seal() and Object.freeze().  The interpreter will now enforce tougher rules in "use strict" mode.  Undeclared variables, for example, will not be executed.

Progress for ECMAScript has been hindered by disagreements and controversy over the last few years.  The fourth edition of ECMA-262, originally targeted for completion by October 2008, would have been the first major update to ECMAScript since the third edition became standard in 1999.  The fourth edition was derailed when a debate between Chris Wilson, Microsoft's platform architect for Internet Explorer, and Brendan Eich, the creator of JavaScript who is now the CTO for Mozilla, surfaced on multiple blogs.  Wilson said that the backwards incompatibility of EC4 would result in "breaking the Web," while Eich gave examples of why  that wouldn't happen.  

As a result, Microsoft, Yahoo, and other opponents of EC4 formed their own camp to design a smaller update for ECMAScript 3 initially called ECMAScript 3.1.  The two camps tried to develop their specs in parallel but differing philosophies kept both specs from being standardized for over a year.  The two teams finally reached a compromise in August 2008: the ECMA Technical Committee 39 (TC39) would focus on ECMAScript 3.1, renamed edition 5.  The recent approval of the EC5 spec is the fruition of many years of obstacles and compromise.  

The fourth edition is not dead yet though.  In 2008, the project was renamed ECMAScript Harmony and will be more modest than the previous EC4 proposal.  The spec will include syntactic extensions but won't include several packages, namespaces, and early binding from ECMAScript 4.  Harmony might be renamed ECMAScript 6th edition now that the 5th edition is the most recent standard.

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