- ECMAScript 5 support in Mozilla
- A look at Mozilla's current — and planned — support for ECMAScript 5.
let, and destructuring assignment.
reduceRight() methods on arrays.
Object.getPrototypeOf, and the string trim methods:
Function.prototype.bind as well as strict mode
- JScript Deviations from ES3 (PDF)
- Describes differences between the ECMAScript ed. 3 standard and its Microsoft implementation (JScript). Also includes information on other browsers (Opera, Firefox, and Safari).