Chapter 8. ECMAScript 5th Edition

In December 2009, ECMA-262 5th Edition, commonly referred to as ECMAScript 5, or simply ES5, was finalized and published by ECMA International. This marked the first significant update to the core JavaScript language in 10 years. ECMAScript 5 is the successor to ECMAScript 3, and is a mostly backwards compatible update of the language that codifies innovation by browser vendors over the past decade and introduces a few new features.

ECMAScript 4 was never realized, and is part of the answer to why the language could go without standardized updates for 10 years. This draft was widely considered too revolutionary an update, and introduced several features that would not work well with existing browsers. To this ...

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