This lesson's interactive features are locked, please to keep using them

ECMAScript

ECMAScript??? I thought we were learning JavaScript!

Well, we are. ECMAScript is the standard that JavaScript is based on. Brendan Eich, the creator of JavaScript, tastefully commented on the name:

"ECMAScript was always an unwanted trade name that sounds like a skin disease."

Its purpose is to help JavaScript (and other languages) maintain compatibility across different runtimes. ECMAScript versions are released yearly, and they have a big impact on how we write modern JavaScript. Some notable versions include:

2009: ECMAScript 5 (ES5) introduced strict mode and JSON support
2015: ECMAScript 6 (ES6) introduced let and const for variable declarations
2017: ECMAScript 8 (ES8) introduced async/await