Introduction to JavaScript programming language

JavaScript is one of the most popular programming languages in the world and is now widely used outside of browsers. In the past few years, the rise of Node.js has unlocked back-end development, which used to be the realm of Java, Ruby, Python, PHP and more traditional server-side languages. Know all the information!

Introduction

JavaScript is one of the most popular programming languages in the world.

Since its establishment in 1995, it has a very low starting point and has come a long way.

As the first (and only) scripting language natively supported by web browsers, it has been at a standstill.

In the beginning, it was not as powerful as it is today. It was mainly used for beautiful animations and the miracle called DHTML at the time.

With the ever-increasing demand of the Web platform, JavaScriptHaveAt the same time, it must take on the responsibility for growth to accommodate the needs of one of the most widely used ecosystems in the world.

The platform introduces many functions through the browser API, but the language has also grown a lot.

Now, JavaScript is also widely used outside of browsers. The riseNode.jsIn the past few years, once Java, Ruby, Python, and PHP and more traditional server-side languages become the domain, back-end development can be unlocked.

Now, JavaScript is still the language that powers databases and more applications, and it is even possible to develop embedded applications, mobile applications, TV applications, and so on. Starting from a very small language inside the browser, it is now the most popular language in the world.

Basic definition of JavaScript

JavaScript is a programming language, it is:

  • High level: It provides abstract concepts so that you can ignore the detailed information of the running computer. It uses the garbage collector to automatically manage memory, so you can focus on the code instead of managing memory locations, and provides many constructs that allow you to deal with powerful variables and objects.
  • Dynamic: Contrary to static programming languages, dynamic languages perform many operations that static languages perform at compile time at runtime. This has advantages and disadvantages, and provides us with powerful features, such as dynamic type input, late binding, reflection, functional programming, object runtime changes,ClosureAnd more.
  • Dynamic input: Variable type is not mandatory. You can reassign any type to a variable, for example, assign an integer to a variable that contains a string.
  • Weak type: Contrary to strongly typed input, weak (or loosely) typed languages do not enforce the type of the object, thus providing greater flexibility, but deny us type safety and type checking (TypescriptAnd flow aims to improve)
  • Explanatory: It is often referred to as an interpreted language, which means that it does not require a compilation stage before the program runs, for example, as opposed to C, Java, or Go. In fact, for performance reasons, the browser will compile JavaScript before executing it, but this is transparent to you: no other steps are involved.
  • Multi-paradigm: The language does not enforce any specific programming paradigm. For example, Java enforces the use of object-oriented programming, while Java enforces imperative programming. You can use object-oriented paradigms, prototypes, and new (from ES6) class syntax to write JavaScript. You can use functional programming style, with first-class features, and even use imperative style (similar to C) to write JavaScript.

If you want to know,JavaScript has nothing to do with Java, This is a bad name choice, but we have to live with it.

JavaScript version

Let me introduce the wordECMAScriptHere. We have a complete guide specifically forECMAScriptYou can do more research in it, but first, you only need to know ECMAScript (also known asES) Is the name of the JavaScript standard.

JavaScript is the implementation of this standard. That's why you hearES6, ES2015,ES2016,ES2017,ES2018and many more.

For a long time, all browsers were running the JavaScript version of ECMAScript3. Due to feature crawling (they tried to add too many things at once), version 4 was cancelled, and ES5 is a huge version of JS.

ES2015, also known as ES6, Also great.

Since then, the person in charge has decided to release a version every year to avoid too much free time between releases and to have a faster feedback loop.

Currently, the latest approved JavaScript version isES2017.

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