JavaScript is a multi paradigm, dynamic programming language which was created by Brendan Eich in May – 1995 within 10 days of time while he was working for Netscape Communications. It was primarily created to perform small scripting tasks and act as a sidekick for the Java programming language for the browsers, with an aim to make the web more dynamic and provide easier access for developers and designers.
The JavaScript Engine
JavaScript is basically a scripting language that can execute anywhere from browsers to laptops to mobile phones, if a JavaScript Engine is present on that device.
All major browsers like Google Chrome, Firefox, Safari, Edge etc come with their own built-in JavaScript Engine to execute JavaScript code. i.e JavaScript commands can directly be typed into an HTML document, and the web browser will be able to understand them. You do not need to install any additional programs or compilers if you wish to use JavaScript.
JavaScript Engines used by browsers :
– Google Chrome uses the V8 Engine
– Mozilla Firefox uses SpiderMonkey
– Microsoft Edge uses Chakra
– Apple uses JavaScriptCore for its Safari Browser
Besides running on the browser, JavaScript can also execute behind the browser. One particular implementation is Node.js.
Node.js is a JavaScript runtime that makes use of the Chrome`s V8 engine to execute JavaScript on the server and create service-side and networking applications.
This states that you are not just limited to create websites using JavaScript. You can write a full fledged robust system using only JavaScript.
JavaScript In The Web
JavaScript is one of the three layers of web development. The other two are HTML and CSS.
First, Lets take a look at how the three layers fit in together with a basic example.
HTML
First we create a button.
<button id=”btnHello”>Say Hello</button>
CSS
We then add some styles to it.
button {
padding: 10px 20px;
border-radius: 25px;
border: solid 1px green;
}
JavaScript
Finally we add some interactivity to our button.
In this case a simple alert message saying Hello.
const button = document.getElementById(‘btnHello’);
button.addEventListener(‘click’, sayHello);
function sayHello() {
alert(‘Hello’);
}
Here is a simple demo
JavaScript is a versatile language in a sense that it can be used to add any kind of interactivity to a plain website. Things like adding click events to buttons, 2D and 3D animations, displaying image galleries, carousels etc can be all achieved by using JavaScript.
