How Does JavaScript Work?


If you’ve been around tech for any length of time, you have most likely heard about javascript and probably know that it’s an important programming language. It’s a scripting language that brings web pages to life by allowing interactive elements to be added like animation, pop-up windows and search bars. It also allows for real-time updates to be displayed on the page without the website having to reload the page. In fact, most video games and applications that run in your browser use javascript to enable their functionality.

JavaScript was originally developed by Netscape to add dynamism and interactivity to early versions of the World Wide Web. It quickly became popular and has since evolved into an ECMA standard, a dedicated JS engine like V8 (which powers Chrome) and server-side environments.

The main advantage of javascript is that it is an interpreted language which means the code can be run immediately without having to be compiled like other languages. This helps with the development process and also ensures that web pages and apps will load faster as well. This is an incredibly powerful feature and is the main reason why it’s a go-to choice for front end developers.

JS is an object-oriented language that has a minimalist syntax. This makes it relatively easy to learn. It is also a dynamic, garbage-collected, single-threaded, interpreted (or just-in-time compiled), prototype-based, multi-paradigm, and dynamically typed language with a non-blocking event loop. While these terms may sound intimidating, they are essentially just a way to describe how JS works. We will take a closer look at each of these concepts in more detail later in the course.

When a piece of jscode is typed into an HTML document, it’s interpreted by the browser’s built-in javascript engine. The code is parsed into a data structure known as an abstract syntax tree (AST). The AST is then converted to machine code, which is translated into 0’s and 1’s by the processor. This code is then executed by the engine.

While javascript is primarily used for front end web development, it’s a versatile enough scripting language to be used for back-end development as well. Creating databases and interacting with databases using javascript is common, as is building web services for a variety of devices like iOS and Android phones and tablets.

There are a number of techniques that can be used to improve the performance of a javascript application, including minimizing interaction with the DOM (document object model) and reducing function calls. These strategies can make a huge difference in how responsive a web page is, especially on older browsers.