Altcademy - a Forbes magazine logo Best Coding Bootcamp 2023

What is JavaScript used for in web development

JavaScript: More Than Just a Programming Language

JavaScript, often simply referred to as JS, is more than just a programming language. It is the backbone of modern web development, enabling developers to create interactive, dynamic, and complex websites. In simpler terms, if a website is a car, then HTML would be the car's frame, CSS its paint job, and JavaScript its engine.

Getting Interactive with JavaScript

The primary purpose of JavaScript in web development is to add interactivity to websites. But what does this mean in layman's terms? To understand this better, consider a basic HTML page as similar to a picture book. The HTML provides the images (the content), and the CSS gives the images color and style (the design). However, these images are static; they don't move or change. JavaScript comes in and adds the ability for these 'pictures' (web components) to move, change, and interact with user commands. It's like turning your picture book into a movie.


// JavaScript code to change a page's background color = "blue";

JavaScript for Dynamic User Interface

JavaScript is also vital for making the user interface (UI) dynamic. In other words, JavaScript can change the information, structure, and style of a webpage without needing to reload it. This might sound complex, so let's break it down with an analogy.

Think of a webpage as a digital vending machine. You put in your request (click a button), and the machine gives you a soda (loads a new page). Without JavaScript, the machine would need to be reloaded every time you want another soda. With JavaScript, it can keep dispensing sodas (change content) without needing to be reloaded.


// JavaScript code to add new content to a page
document.getElementById("demo").innerHTML = "Hello, World!";

JavaScript for Form Validation

Another important use of JavaScript is form validation. This is a way of checking that the information users enter into a form on a website is correct before it's sent off to the server. Think of it as a bouncer at a nightclub, checking everyone's IDs before they're allowed in. If the ID isn't valid, the person isn't allowed in.


// JavaScript code for a simple form validation
function validateForm() {
    var x = document.forms["myForm"]["fname"].value;
    if (x == "") {
        alert("Name must be filled out");
        return false;

JavaScript for Animations

JavaScript is also used to create animations on websites. This is like adding special effects to your movie, making it more engaging and visually appealing. It can be anything from a simple color change when you hover over a button, to complex animations like a slideshow.


// JavaScript code to change the color of a button when the mouse hovers over it
document.getElementById("myButton").onmouseover = function() { = "red";

JavaScript for Communication with Server

JavaScript is also used to communicate with servers. This is like a postman delivering letters (data) between your house (the client) and the post office (the server). JavaScript can send data to the server, and also retrieve data from it. This is crucial for any website that needs to handle user data, like a social media platform or an online store.


// JavaScript code to fetch data from a server
    .then(response => response.json())
    .then(data => console.log(data));


Imagine a magic wand that can transform a static, unresponsive picture book into an interactive, dynamic, and engaging movie. That's what JavaScript does in the world of web development. It adds interactivity to web pages, makes UI dynamic, validates user input, creates animations, and communicates with servers to handle user data. So next time you're on a website and marvel at its functionality, remember that JavaScript is probably behind the scenes, working its magic. Whether you're a budding web developer or a curious user, understanding JavaScript's role in web development gives you a deeper appreciation of the complex workings of the digital world.