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What is JavaScript written in

The Basics: What is JavaScript Written In?

JavaScript, often simply called JS, is one of the most popular and widely used programming languages today. But what is JavaScript written in? This question may sound a bit confusing, especially for beginners. In simple terms, JavaScript is written in plain text, just like other programming languages.

But let's delve a little deeper. When we say "What is JavaScript written in?", we are probably looking into the language or languages that were used to create JavaScript itself. To answer this, JavaScript was originally developed in C and C++.

Understanding C and C++

C and C++ are both general-purpose programming languages. If you imagine programming languages as tools in a toolbox, then C and C++ are like a hammer and a screwdriver. They're basic but very essential tools, and they can be used to create other tools.

C was developed in the 1970s and is one of the oldest programming languages still in use today. It's known for its efficiency and control.

C++, on the other hand, is an extension of C that was developed in the 1980s. It introduced new features like classes and objects, making it easier to manage and organize code.

Let's dive into an example of how C and C++ look like. Here's a simple C++ program that prints "Hello, World!" to the console:

#include <iostream>

int main() {
    std::cout << "Hello, World!";
    return 0;

In this code, #include <iostream> is a preprocessor command that tells the compiler to include the iostream library. std::cout is used to send output to the standard output stream, which is typically the console.

When Brendan Eich created JavaScript in 1995, he chose to write it in C (and later C++) because these languages were well-suited for system-level programming. They offered the low-level control necessary to create a high-level language like JavaScript.

Imagine you're building a house. C and C++ are like the raw materials — the bricks, cement, and steel. JavaScript, on the other hand, is like the finished house. You need the raw materials to build the house, even though people living in the house might not see them directly.

The Evolution of JavaScript

JavaScript has evolved significantly since its creation. Today, most modern web browsers implement JavaScript using a JavaScript engine, which is a program that converts JavaScript code into lower-level or machine code that can be executed by the computer.

Notably, Google's V8 engine — used in Chrome and Node.js — is written primarily in C++. Here's a fun fact: even though JavaScript was initially written in C, modern JavaScript (like that used in the V8 engine) is now primarily written in C++!


So, to answer the question "What is JavaScript written in?" — JavaScript code itself is written in plain text, but the language was originally developed using C and C++. Modern implementations of JavaScript, like Google's V8 engine, are primarily written in C++.

Remember, just as a beautifully constructed house starts with basic materials like bricks and cement, high-level languages like JavaScript are built using more basic, lower-level languages like C and C++. This understanding gives us a deeper appreciation for the intricate layers of technology that makes our modern web experience possible.

Whether you are a web developer, a software engineer, or just an enthusiast, understanding the foundations of JavaScript can be really enlightening. It brings us closer to understanding the core of software development and how languages work together to create the digital experiences we see every day.

Happy Coding!