Why? JavaScript is primarily known as the language of most modern web browsers, and its early quirks gave it a bit of a bad reputation. However, the language has continued to evolve and improve. JavaScript is a powerful, flexible, and fast programming language now being used for increasingly complex web development and beyond!.
Since JavaScript remains at the core of web development, it’s often the first language learned by self-taught coders eager to learn and build. We’re excited for what you’ll be able to create with the JavaScript foundation you gain here. JavaScript powers the dynamic behavior on most websites, including this one.
JavaScript is the most powerful and versatile web programming language. It is used for making the websites interactive. JavaScript helps us add features like animations, interactive forms and dynamic content to web pages.
What is JavaScript?
JavaScript is a programming language used for creating dynamic content on websites. JavaScript is an interpreted language that executes code line by line providing more flexibility. It is a commonly used programming language to create dynamic and interactive elements in web applications. It is a :
- Lightweight,
- Cross-Platform, and
- Single-threaded programming language.
Applications of JavaScript Programming
JavaScript is one of the most widely used programming languages (Front-end as well as Back-end). It has its presence in almost every area of software development. I’m going to list few of them here:
- Client side validation − This is really important to verify any user input before submitting it to the server and JavaScript plays an important role in validating those inputs at front-end itself.
- Manipulating HTML Pages − JavaScript helps in manipulating HTML page on the fly. This helps in adding and deleting any HTML tag very easily using JavaScript and modify your HTML to change its look and feel based on different devices and requirements.
- User Notifications − You can use JavaScript to raise dynamic pop-ups on the webpages to give different types of notifications to your website visitors.
- Game Developments − JavaScript contains multiple libraries and NPM packages to design graphics for the game. We can use HTML, CSS, and JavaScript with libraries to develop the games.
- Mobile applications − We can use frameworks like React Native to build feature-rich mobile applications.
Prerequisites to Learn JavaScript
For this JavaScript tutorial, it is assumed that the reader has prior knowledge of HTML coding. It would help if the reader had prior exposure to object-oriented programming concepts and a general idea of creating online applications.
JavaScript Jobs
Here are the most popular companies offering the role of JavaScript developer. You can land as an employee with a high package after pursuing your career as a JavaScript developer.
- Amazon
- Microsoft
- Apple
- Adobe
- PayPal
- Many more…
Careers Opportunities in JavaScript
There are several career paths that you can choose after learning JavaScript. Here, we have listed some of them.
- Front-end developer
- Back-end developer
- Full-stack developer
- Web developer
- Game developer
- Mobile App developer
- DevOps Engineer
- Many other roles
JavaScript Frameworks and Libraries
JavaScript frameworks are used to develop a whole application. It defines the structure of your application.
The framework can have pre-built components and other functionalities that can help you reuse the code of the application, improve code readability, and avoid duplicity.
Here, we have explained the most popular JavaScript frameworks which you can use for website development, app development, backend development, etc.
- React
- Angular
- Vue.js
- Ember.js
- Node.js
- Backbone.js
- Next.js
- Mocha
- Meteor.js
- Polymer
In JavaScript, a library is a set of pre-defined functions, classes, methods, objects, etc. You can import the library in your JavaScript code by using the CDN or downloading it locally. After adding the library to the project, you can use the library’s pre-written functions, classes, etc., in the code.
Here, we have given a list of the most popular JavaScript libraries.
- jQuery
- Axios
- Chart.js
- D3.js
- Socket.io
- Underscore.js
- Lodash
- Three.js
Console
The console is a panel that displays important messages, like errors, for developers. Much of the work the computer does with our code is invisible to us by default. If we want to see things appear on our screen, we can print, or log, to our console directly.
In JavaScript, the console keyword refers to an object, a collection of data and actions, that we can use in our code. Keywords are words that are built into the JavaScript language, so the computer recognizes them and treats them specially.
One action, or method, that is built into the console object is the .log() method. When we write console.log() what we put inside the parentheses will get printed, or logged, to the console.
It’s going to be very useful for us to print values to the console, so we can see the work that we’re doing.
console.log(5);
This example logs 5 to the console. The semicolon denotes the end of the line, or statement. Although in JavaScript your code will usually run as intended without a semicolon, we recommend learning the habit of ending each statement with a semicolon so you never leave one out in the few instances when they are required.
You’ll see later on that we can use console.log() to print different kinds of data.
A “Hello World!” Example
JavaScript is one of the most popular modern web technologies! As your JavaScript skills grow, your websites will enter a new dimension of power and creativity.
However, getting comfortable with JavaScript is more challenging than getting comfortable with HTML and CSS. You may have to start small, and progress gradually. To begin, let’s examine how to add JavaScript to your page for creating a Hello world! example. (Hello world! is the standard for introductory programming examples.)
- Go to your test site and create a new folder named
scripts. Within the scripts folder, create a new text document calledmain.js, and save it. - In your
index.htmlfile, enter this code on a new line, just before the closing</body>tag:
<script src="scripts/main.js"></script>
3. This is doing the same job as the <link> element for CSS. It applies the JavaScript to the page, so it can have an effect on the HTML (along with the CSS, and anything else on the page).
4. Add this code to the scripts/main.js file:
const myHeading=document.querySelector("h1);
myHeading.textContent = "Hello world!";