What's JavaScript?

The JavaScript (JS) technology appeared at 1995, as a way to develop interactive web-pages in the Netscape Browser, which was one of the firsts browsers of all time.

This scripting language has nothing to do with the programming language Java.

JavaScript gained a lot of popularity, that's why nowadays it's used in all major web browsers, including: Firefox, Chrome, Microsoft Edge, Safari, Opera, etc... That's why the decision of standardizing the language was taken with the help of the European Computer Manufacturers Association (ECMA) making the JavaScript standard called ECMAscript.

This helps the different browsers to know the standard rules of JavaScript

Different browsers, uses different JS Engines to process and run JavaScript within them. For example, Chrome uses the V8 Engine, Firefox uses SpiderMonkey and Safari uses JavaScriptCore.

What's a JavaScript Engine?

A JavaScript Engine work is to receive the source code and convert it to something the computer can understand. All of the previous mentioned engines follows the ECMAscript standard to do their work, but it's up to them individually to decide how the will translate the source code to something that's useful.

So, what's the work of JavaScript?

As mentioned before, JavaScript's work is to add interactivity to a web-page without the need of this one to reload. It simply adds the logic to a website.

There are projects like Node.js and Deno that take out JavaScript of the browsers, allowing to use the language in other places but the browser.