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Learn JavaScrip and Get Good at It

JavaScript is a light-weight scripting language, mainly used to develop web sites and web-based applications.

JavaScript is a light-weight scripting language, mainly used to develop web sites and web-based applications.

If you’re wondering what is a scripting language, it basically means your code will need a special program to run. This program is also known as a runtime environment – or simply an environment.

In a front-end development context, the environment is usually a web browser, or to be precise, it’s a JavaScript engine embedded into the web browser (more on this below).

A web browser downloads your web page (including your JavaScript code) from your server, renders the HTML, and runs your JavaScript code; The output would be an amazing intractable web page, made by you.

Usage of JavaScript isn’t limited to web browsers, though; There are times you might want to use JavaScript to make something other than a web page.

One of these non-browser environments is Node.js. Node.js is a program, which enables you to use JavaScript in backend development, such as creating content management systems or even command-line programs – Sky is the limit when JavaScript steps beyond its web browser roots.

Although JavaScript brand is licensed to the Oracle Corporation, each web browser vendor has its own implementation of JavaScript, which is called a JavaScript engine – a.k.a JavaScript runtime. For example, Google Chrome has its own implementation of a JavaScript engine, known as V8, while the Mozilla team calls theirs, SpiderMonkey.

JavaScript engines are developed and maintained separately from web browsers, but they are eventually embedded into web browsers; They have one job: run your JavaScript code.

Technically, you can take the source code of a JavaScript engine and use it in your program; That’s exactly what Ryan Dahl did. He took Google’s V8 JavaScript engine and used it alongside a C++ program. The result of this marriage was the birth of Node.js.

If each web browser vendor has their own implementation of JavaScript, then, what’s the guarantee that my code would run consistently across different web browsers? you may ask.

Browser vendors must implement their JavaScript engine based on a language standard called ECMAScript (by ECMA International). ECMAScript ensures the consistency of JavaScript code across browser and non-browser environments.

It would be a disaster if two different web browsers, interpret the same JavaScript code differently, just because they use different JavaScript engines. ECMAScript ensures it won’t happen.

ECMA International publishes new editions of ECMAScript every once in a while. Consequently, browser vendors (such as Google and Mozilla) would have to update their JavaScript engines accordingly.

The latest version of ECMAScript is ECMAScript 2015, which is known as ES6; So every time you hear people talking about ES6 code, they are simply talking about a JavaScript code, which is written based on the ES6 specifications.

In Case You're Wondering...

JavaScript can be used for a variety of use cases, depending on the runtime environment in which it is used.

On a web page, you can manipulate elements on the page, validate user data, make image-sliders, build calculators, create cool animations and games, and a lot more.

However, when it’s used outside of the browser, say it’s executed by Node.js, you can create almost any application from web servers to command-line utilities.

No, JavaScript and Java are two different languages.

Java is an object-oriented programming language. A Java program is compiled and run on any platform that supports Java, which basically means any machine that has the Java Runtime installed.

However, JavaScript is a scripting language, which is a just-in-time compiled language, which basically means it is compiled at execution time by the runtime (a JavaScript engine in this case).

Based on Glassdoor, the national average salary for a JavaScript developer is $79k a year in the United States, which goes up to $117k a year.

JavaScript is used by almost every company these days. From small teams to tech giants such as Microsoft, Google, Facebook, eBay, LinkedIn, Netflix, Uber, etc.

JavaScript is almost everywhere.

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