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ISO/IEC and Ecma International ratify “ES5.1”, the latest ECMAScript specification of Ecma International

Members of Ecma International work together to create official ECMAScript test suite


Geneva, Switzerland, 30 June 2011

ISO, the International Organization for Standardization, IEC, the International Electrotechnical Commission and Ecma International have ratified ECMA-262 edition 5.1, signifying its recognition as an International Standard. This will facilitate its adoption by government organizations around the world, or its inclusion in public procurement requirements.

ECMA-262 defines the ECMAScript scripting language, more commonly known as JavaScript™, the dynamic scripting language used to create web pages with dynamic behavior. It is an essential component of every web browser. The latest version will be also published as ISO/ IEC 16262 edition 3. Mr. Brendan Eich, CTO at Mozilla and a major contributor to the standards process, said "ECMA-262 Edition 5.1 creates a solid base for future evolution of the standardized JavaScript language by delivering crucial functionality such as strict mode and the Object Meta-Programming APIs."

Release of the identical ECMA-262 edition 5.1 completes nearly a decade of work by Ecma Technical Committee 39 to ensure consistency in scripting across web browsers, and to enable the existence of interoperable web applications. The new ECMA-262 edition 5.1 is a minimal but needed update of edition 5, approved in December 2009 by the Ecma General Assembly. With additional editorial corrections and bug fixing it makes the implementation of the latest ECMA-262 edition easier and allows better interoperability among web applications. It is identical to ISO/ IEC 16262 edition 3.

For the first time, Ecma will publish a standardized test suite for the latest version of ECMA-262 edition 5.1, known as Test262. Via this suite, developers will be able to test how closely implementations of ECMAScript follow the specifications in ECMA-262 edition 5.1. The test suite will be published as an Ecma Technical Report and will be made available to developers via the normal Ecma distribution channels and The test suite will be released in increments with the first version planned for December 2011 and updates provided later.

The test suite has been created by the Ecma Technical Committee 39, with committee members including Mozilla, Microsoft, Google and many others helping to make the suite a resource that helps developers provide fine-tuned feedback on support for the standard.

Over 10,000 tests cover the specification today. Test suites are an integral part of the process needed to create interoperable cross-platforms standards.

About Ecma International

Since its inception in 1961, Ecma International (Ecma) has developed standards for Information and Communication Technology (ICT) and Consumer Electronics (CE). Ecma is a non-profit industry association of technology developers, vendors and users. Experts from industry and other organizations work together at Ecma to develop standards. Ecma submits its work for approval as ISO, IEC, ISO/IEC JTC 1 and ETSI standards and is a frequent practitioner of “fast-tracking” of specifications through the standardization process in international standards organizations. Download ECMA-262 edition 5.1 or any other publication free of charge from the Ecma International website.

For more information: please contact Dr. Istvan Sebestyen, Secretary General of Ecma International. Email: