ES3

Es3, short for ECMA-262 third edition, is the third edition of the ECMAScript language specification published by ECMA International in 1999. It standardizes the core semantics and features that underpin JavaScript and other ECMAScript implementations.

Compared with earlier editions, ES3 introduced standardized error handling with try/catch/finally, improved regular expression handling, and more consistent behavior of built-in objects such as String, RegExp, Array, Date, and Math across engines. It also defined clearer rules for property access and object creation in an effort to reduce cross-browser discrepancies.

Despite its limitations by modern standards, ES3 remained the baseline for JavaScript implementations throughout the 2000s and influenced browser behavior well into the era of ES5. In 2009–2010, ES5 introduced further features, including strict mode and native JSON support; the ES4 proposal was ultimately abandoned, with many of its ideas carried forward into ES5 and beyond.

Es3’s legacy lies in providing a more stable, interoperable foundation for client-side scripting and server-side JavaScript implementations, making it easier for developers to write portable code.

See also ECMA-262, JavaScript, ECMAScript.

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