How Does JavaScript Work?


JavaScript is an interactive programming language that can be used to add dynamic elements to a web page, such as video, images, animations and more. It’s one of the key components of HTML and CSS, a set of standard web technologies that together form the foundation for most web pages. Without it, your web page wouldn’t be able to do what it does today.

How Does JavaScript Work?

JavaScript works in the background of modern web browsers. Most modern browsers have built-in JavaScript engines that receive code from a JavaScript program, validate it and convert it to machine code. When the code is ready, the engine Parser then creates an Abstract Syntax Tree and submits it for execution.

In the first phase, the JavaScript engine reads the code and allocates memory to each variable and function. It also tries to create an Execution context for the code. Then, it starts executing the code one piece at a time. If it doesn’t find the variable or function that it’s looking for, it returns to the memory creation phase.

When the JavaScript engine comes across var a = 2, it assigns 2 to ‘a’ in memory. After that, it starts executing the rest of the code.

Unlike other languages, it’s single-threaded at runtime, which means that any code that takes a long time to execute will block anything else. This makes it a good choice for front-end development but can cause issues with older browsers.

A JavaScript program starts with a rudimentary baseline compiler. This compiles the code into an intermediate representation called bytecode, which is then fed to the interpreter. This interpreter then converts this bytecode to machine code and runs it on the CPU.

It’s a lightweight and simple to use language that’s easy to understand, but it can be slow to run when used to create complex programs. The lack of type system in JavaScript means that it’s not as efficient as a statically typed language like C or C++.

To make sure it doesn’t take up too much of the CPU, JavaScript’s syntax is minimalist, which can be a good thing in some cases. It’s also easy to implement and a lot of people love it because it’s so lightweight.

The earliest incarnations of JavaScript were created in 1995 and were originally named LiveScript. They were created for Netscape Navigator, a popular Web browser at the time.

Since then, JavaScript has become a vital component of the Internet’s ability to provide a variety of dynamic and interactive services. From Facebook’s timeline to Google’s search suggestions, most of the functions and applications that make the Internet an essential part of our daily lives are created with this versatile programming language.

In the end, we hope this post gave you a clearer understanding of how JavaScript works in the background of your computer. With that knowledge, you can build your next dynamic web page or application and improve your business’s overall user experience.