Differences in javascript versions

JavaScript is a widely used programming language used to create web applications and websites. During the development of the JavaScript language, many versions have appeared. This article will discuss the differences between different versions of JavaScript and explore their characteristics and uses.

Classification of JavaScript versions

JavaScript versions are divided into two categories: ECMAScript and non-ECMAScript. ECMAScript is the official specification for JavaScript, developed by the European Computer Manufacturers Association (ECMA). The non-ECMAScript version is an enhanced version based on ECMAScript and is developed by browser manufacturers or other third-party developers.

ECMAScript version

ECMAScript is the main specification version of JavaScript. It defines JavaScript's core language features and standard library. Below are a few different versions of ECMAScript.

ECMAScript 1

ECMAScript 1 is the first formal specification of JavaScript, published by the ECMA-262 committee in 1997. This version introduces the basic language structures of JavaScript, such as variables, functions, objects and basic syntax and standard libraries.

ECMAScript 2

ECMAScript 2 was released in 1998, adding regular expressions and more basic syntax.

ECMAScript 3

ECMAScript 3 was released in 1999 and is one of the most popular and widely used versions. This version introduces some very important features, such as try-catch statements, strict mode, getter and setter methods, array methods, regular expressions and JSON (JavaScript Object Notation, etc.).

ECMAScript 4

ECMAScript 4 was not adopted in 2008 because the content of this version proposal was too large. It was supposed to introduce many new features, such as classes, modules, iterators and generators, but was ultimately not adopted due to its large size and browser compatibility issues.

ECMAScript 5

Released in 2009, ECMAScript 5 was an important version that marked major improvements to JavaScript. It introduces strict mode, JSON objects, and some new array, function, and string methods. In addition, ECMAScript 5 introduced two object extension methods, Object.create() and Object.defineProperty().

ECMAScript 6

ECMAScript 6 (also known as ECMAScript 2015) is the latest JavaScript version, released in 2015. It introduces new features such as classes, modules, arrow functions, destructuring assignment, Rest parameters, default parameters, iterators and generators. In addition, ECMAScript 6 also introduces complex features of object-oriented programming, such as Symbol, Proxy, and Reflect.

ECMAScript 7

ECMAScript 7 (also known as ECMAScript 2016) is a minor version released in 2016, which introduces some new features, such as the Array.prototype.includes() method, Exponential operator (**), async/await and Object.values ​​methods.

ECMAScript 8

ECMAScript 8 (also known as ECMAScript 2017) is another minor version released in 2017. This version introduces new features such as async/await and Object.entries() methods, shared memory, and atomic operations.

Non-ECMAScript version

The non-ECMAScript version refers to the enhanced version of JavaScript based on the ECMAScript specification developed by browser manufacturers or other third-party developers. These versions are often called "DOM scripts" or "browser scripts".

The non-ECMAScript version mainly focuses on providing enhanced client-side scripting functions for web development, such as operating web page elements, handling events, creating animations and network communications, etc.

The following are several common non-ECMAScript versions:

JScript

JScript is the name of a variant of JavaScript proposed by Microsoft in 1996 and used in the Internet Explorer browser version of. It's basically the same as JavaScript, with some minor differences. JScript is considered the version of JavaScript for Internet Explorer.

ActionScript

ActionScript is an ECMAScript-based scripting language created by Adobe for creating animations and interactive applications for the Flash platform. ActionScript is based on the ECMAScript specification and extends its temporal and two-dimensional action control features.

TypeScript

TypeScript is a variant of JavaScript created by Microsoft Corporation that provides stricter type checking and extended capabilities for object-oriented programming. The TypeScript compiler converts TypeScript code into JavaScript to run on different browsers and devices.

Summary

JavaScript has evolved into a powerful programming language. As it continues to develop, various versions are constantly emerging. Whether it is the ECMAScript specification version or the non-ECMAScript version, they have their own unique features and uses. As developers, understanding these differences will help us better understand the history, current situation, and future direction of JavaScript.

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