1. Introduction to JavaScript Language

This JavaScript tutorial is an introduction to JS programming language that explains the basics and working of this wonderful language. In this course, we will explore some fundamentals of JavaScript programming, and further, we will get some know-how of what this language is capable of. Moreover, in this intro tutorial, we will learn some key concepts and functionalities of JavaScript programming.


JavaScript Has Wonderful Features!

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Tutorial Contents:

  1. Intro to JavaScript
  2. Basics of JavaScript
  3. How it Works?
  4. Benefits of JavaScript
  5. Conclusion

1.1. What is JavaScript?

  • Primarily, JavaScript is a programming language that runs in a browser and aids HTML along with CSS to make web pages dynamic and responsive.
  • JavaScript or JS is the most popular programming language among developers and is widely used throughout the world.
  • Further, there is no need to compile the JS code as all modern browsers have built-in JavaScript support.
  • Therefore, a developer does not have to set up or download JavaScript in order to start developing with JS.
  • Moreover, all modern web browsers support JavaScript and it has a huge developer community.


Importantly, JavaScript and Java are both different languages, and both of them have different syntax, functionality, and usage.

1.2. Need For JavaScript?

  • Back in 1995, when Brendan Eich was working at Netscape Communications Corporation, he developed JavaScript.
  • Initially, the developers created dynamic and interactive web pages using Java and Flash languages, and there was a need for code compilation to get the functionality.
  • Therefore, Brendan was tasked to develop a new high-level language, that could work without the need for compilation or use of any third-party plugin.
  • Thus, JavaScript came into being with its original name Mocha, and it enabled web developers to develop dynamic content with much ease and swiftly.
  • Resultantly, a new chapter started in the evolution of the web, as JS allowed programmers to develop dynamic websites more conveniently with greater user interaction.


ECMAScript is the official and original name of the JS language.

1.3. What are JavaScript Filename Extensions?

There are three file name extensions for JavaScript files, which we can use to build JS projects.

Extension Description
.js This is the most widely used and known JavaScript extension, and it is the default JS programming extension.
.cjs The .cjs is a newer file extension of JavaScript programming, and it is used for CommonJS modules, which are used in Node.js applications with the help of require() function.
.mjs JavaScript has this latest extension used for ECMAScript modules, which work with the import and export statements and are intended to be utilized in web applications.

2. What are the Basics of JavaScript?

This introduction tutorial on JS language explores the basics of JavaScript in detail. Basically, JavaScript is a lightweight and interpreted high-level language, and it drew the attention of developers from the very beginning due to its usefulness. Therefore, it has a huge developer community, and a lot of resources, libraries, and frameworks are available for working with JS programming.

2.1. Basics of JavaScript Language

Below are the basics of JavaScript programming, which any JS developer must learn in order to be a good developer.

  • First of all, JavaScript is a high-level programming language and is often known as a just-in-time compiled language.
  • Importantly, Java is totally different from JavaScript, which is a completely different programming language.
  • It makes the web pages dynamic and interactive efficiently.
  • Further, JavaScript is a client-side scripting language, which means it is run by the browser rather than the server.
  • All modern web browsers support JavaScript.
  • As it is an interpreted language, therefore we do not need to compile the JS code in order to make it work.
  • JavaScript is also used with other web languages like HTML and CSS to develop independent web applications.
  • Moreover, JS supports the objected-oriented, functional, and imperative programming styles.
  • Interestingly, we can also develop desktop and mobile applications with the help of JavaScript programming.
  • We can also utilize JavaScript for server-side development using technologies like Node.js.

3. How Does JavaScript Work?

Further, in this introduction tutorial, we will discuss how JavaScript works and how can we get more out of its features. This introductory course explains a basic and an advanced example to understand JS coding and its usefulness.

3.1. JavaScript Basic Example

One of the many features of JavaScript is that it can interact and modify the HTML Markup dynamically. Check the below simplest instance, which uses the getElementById() JavaScript method.


document.getElementById( "demo" ).innerHTML = "Hello World!";

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  • This simplest JS example uses the method getElementById().
  • The JS method is used to select elements of HTML markup using the attribute ID.
  • Further, we can perform various operations on the selected element.
  • Visit CodeLab for the complete working of the above JS code and its results.

3.2. JavaScript Advanced Example


function upperCaseString() {
	index = 0;
	intervalId = setInterval(function() {
		if (index < originalString.length) {
			output.textContent = output.textContent.slice(0, index) + originalString[index].toUpperCase() + output.textContent.slice(index + 1);
		} else {
	}, 20);

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  • This advanced JS example explains the process to convert a string to uppercase or lowercase.
  • The above code box contains the JavaScript code to convert the string into uppercase.
  • It uses the toUpperCase() JavaScript method to make the string in uppercase.
  • There are several other functions and methods used in this code, which we will learn later in this JS tutorial.
  • Click the button to visit CodeLab to experience the results and all the code.

4. Advantages of JavaScript

Further, in this introduction tutorial, we will learn and discuss the numerous advantages of using JavaScript due to its functionality and adaptability. Consider the below advantages of developing in JavaScript programming.

  • Firstly, the using language is that it is lightweight.
  • Interestingly, we do not have to install or download JavaScript as it is already available in all browsers.
  • It helps in creating interactive web applications creating more engagement of the users.
  • Moreover, we can build websites, games, and standalone applications with the help of JavaScript.
  • JavaScript can build dynamic websites with the ability to update the content without refreshing the page.
  • We can also deploy JavaScript code to create real-time notifications, updates, and other asynchronous functionality.
  • Moreover, we can build browser extensions and add-ons with the help of JavaScript.
  • With Node.js technology, we can create server-side applications using JavaScript programming.
  • We can conveniently build cross-platform mobile applications using React Native framework.
  • Lastly, due to the huge developer community, we can easily find resources, tutorials, and help regarding JS.

5. Conclusion

Lastly, we will conclude this introduction tutorial by saying that, JavaScript is a versatile and useful language that has plenty of uses. The basics of JavaScript are important for developers to make use of the JS functionalities in various applications. Further, we explained JS programming with the help of a basic and an advanced example to let you know what JavaScript is capable of. Moreover, some advantages or benefits are described to build the interest of the developers to use the wonderful JavaScript language.

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