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What is JavaScript? The Guide to the Best Known Programming Language

Published on April 22, 2022
What is JavaScript? The Guide to the Best Known Programming Language

In the world of programming languages, JavaScript is undoubtedly the most popular. If you have ever worked with a web page or app, you have come into contact with JavaScript.

While it is most commonly used in web browsers, that is not all that it is limited to. With its many features and capabilities, it is no wonder why so many developers choose to work with JavaScript. This blog post will explore everything there is to know about JavaScript.

History of JavaScript

JavaScript was created in 1995 by Brendan Eich while he was working for Netscape. It was initially known as Mocha, then LiveScript, before finally settling on JavaScript.

The name is a bit of a misnomer since the language has little to do with Java. However, at the time of its creation, Java gained popularity, and Netscape wanted to take advantage of that.

Even though it shares the name with Java, JavaScript is a very different language. It is a scripting language that is interpreted rather than compiled like Java.

This makes JavaScript much easier to work with since you do not have to go through the compiling process every time you make a change.

JavaScript was first introduced in Netscape Navigator two years after its creation and quickly gained popularity.

It was soon adopted by Microsoft and included in Internet Explorer. Today, all major web browsers support JavaScript, and it has become the standard for front-end development.

What is JavaScript?

JavaScript is a scripting language that typically runs on the client-side. This means it is executed on your computer rather than on the server like some other languages.

When you visit a website, the JavaScript code will run in your web browser and allow for things like interactive elements or dynamic content. These include:

  • Fillable forms
  • Interactive slideshows and scrolls
  • Animated graphics
  • Video and audio playback

JavaScript is a versatile language and can be used for much more than just web development. It can also be used for:

  • Desktop applications
  • Mobile app development
  • Games (2D & 3D)
  • IoT devices
  • Server side scripting with Node.js

While most JavaScript applications run on the client side, there are some server-side applications that it is useful for, such as creating web servers. With its many capabilities, it is no wonder that JavaScript is so popular.

How does JavaScript work?

Now that we know a bit of the history of JavaScript and what it can be used for, let's take a look at how it works.

JavaScript's open source code is executed in your web browser by an engine. The most popular engine is Google's V8-Engine used in the Chrome web browser. Other popular browsers like Firefox and Safari use their engines.

When you visit a website, the engine will interpret the JavaScript code on the page and run it. This interpretation is what allows for things like animated graphics or fillable forms. The engine will also keep track of any changes made to update the page accordingly.

One of the benefits of using JavaScript is that it can be used to create interactive web pages. That means you can provide a better experience for your users by making your page more responsive.

Let us show you a simple example:

<!DOCTYPE html>

<p id="demo">JavaScript can change HTML content.</p>

<button type="button" onclick='document.getElementById("demo").innerHTML = "Hello JavaScript!"'>Click Me!</button>


The output for this code snippet would be:

JavaScript can change HTML content.

JavaScript code is written in something called an editor. This is where you will write your code and save it to be interpreted by the engine.

There are many different editors available, both free and paid. Some popular ones include Visual Studio Code, Atom, Github, and Sublime Text.

Once you have written your code in the editor, you need to save it as a .js file. This is the file extension for JavaScript files.

You can then upload it to your web server to be accessed by the engine when someone visits your site.

JavaScript is a very powerful language that can be used for various purposes. It is easy to get started with, and many resources are available to help you learn.

Features of JavaScript

JavaScript has numerous features that make it attractive to developers. Here are some of the most notable:

Cross-platform compatibility

One of the most appealing features is its cross-platform compatibility. This means that JavaScript code can run on any platform, regardless of the operating system. Each browser has its engine which will interpret the code, so there is no need to worry about platform compatibility.

This is in contrast to some other languages, which may require different versions for different platforms. This can be a significant advantage when developing for the web as it saves you time and effort to maintain multiple codebases.

Communication between applications

Another great feature of JavaScript is its ability to communicate with other applications. This is made possible through an API (Application Programming Interface). An API allows two applications to exchange data and communicate with each other. APIs are used for everything from user experience testing to showing local weather.

For example, if you were developing a web page that needed to access data from a database, you could use the APIs provided by the database software to request the data. The JavaScript code on your web page would then receive the data and display it to the user.

Another example would be a restaurant that wants to make booking a reservation easier for their customers. To do this, they need to make it possible online. So, they program OpenTable's API into their website so that users can book a table directly from their site.

These are just small examples of what is possible with JavaScript and its APIs. As you can see, the ability to communicate between applications opens up a whole world of possibilities for developers.

Object-oriented programming

JavaScript is also an object-oriented scripting language. This means that it uses objects to store data and functions. You can think of an object as a collection of data and functions related to each other.

For example, let's say you were developing a web page that displayed information about different countries. You could create an object for each country that stored the data about that country. The data could include the population, area, capital city, etc. The functions could be used to calculate things like population density or average life expectancy.

Object orientation is a powerful programming paradigm that can help you organize and structure your code more efficiently.


Another great feature of JavaScript is its portability. This means that code written in one environment can be easily moved to another. For example, if you were developing a web page and wanted to move it to a mobile app, you could do so with minimal effort.

This is because JavaScript is an interpreted language, and the code is not compiled into a machine-readable format. Instead, it is interpreted by the browser or engine at runtime.

This benefits making JavaScript very portable as there are few restrictions on where it can be run.


JavaScript has excellent support from both browser vendors and the community. Browser vendors are constantly working to improve the performance of JavaScript and to add new features.

The community is also very active, with many developers creating libraries and frameworks that make development easier. Many online resources, such as tutorials and documentation, can help you learn more about JavaScript.

JavaScript applications

Now that we have learned about some essential features of JavaScript, let's take a look at the applications it can be used for.

Web development

One of the most popular uses for JavaScript is web development. With JavaScript, you can create interactive web pages that respond to user input. You can also create animations and games that run in the browser.

JavaScript is also used to create web applications. These are web-based applications that perform tasks like managing databases or processing payments. Examples of this in action are Google Docs and Trello.

Mobile development

JavaScript can also be used for mobile development. With frameworks such as React Native, you can create native apps that run on both iOS and Android devices.

React Native uses a different approach to mobile development than traditional methods. Instead of using platform-specific languages, such as Java for Android or Swift for iOS, it uses JavaScript.

This benefits making development faster and easier as you only need to learn one language. It also makes it easier to port your code between platforms. Mobile apps written in this language include Facebook, Instagram, and Airbnb.

Desktop development

JavaScript can also be used for desktop development. With Electron, you can create cross-platform desktop applications using web technologies.

This is a popular approach as it allows you to reuse code from your web applications. It also makes it easy to distribute your application as it can be run on multiple operating systems.

Examples of desktop applications written in this language include Slack, Visual Studio Code, and WhatsApp.

IoT development

JavaScript can also be used for IoT development. This involves developing applications that run on devices such as sensors, wearables, and connected appliances.

One of the benefits of using this language for IoT development is that it is lightweight and has a small footprint. This means it can be run on devices with limited resources, such as sensors.

Another benefit is that it is easy to develop applications in JavaScript as there are many libraries and frameworks available.

Examples of IoT applications written in this language include Nest, Philips Hue, and Belkin WeMo.

Java vs JavaScript

The differences between Java and JavaScript are many:

  1. Java is a compiled language, while JavaScript is an interpreted language.
  2. Java is a statically-typed language, while JavaScript is a dynamically-typed language.
  3. Java runs on a virtual machine while JavaScript runs in the browser or engine.
  4. JavaScript is much easier to learn than Java, but it is also less complex. Thus, it is suitable for the development of smaller applications.
  5. Java is more suited for developing large, complex applications. You can learn it in any environment, whether virtual machines or browsers.
  6. Additionally, both require the use of specific plugins. None of these plugins are interchangeable.

Is JavaScript secure?

Even though JavaScript is a well-respected language, some security concerns exist.

One of the main concerns is that JavaScript is primarily a client-side language, meaning that the code is executed on the user's computer rather than on the server. This can be a problem, as malicious code can be injected into your site without you knowing about it.

Another concern is that since JavaScript is a dynamic language, it can be difficult to catch errors. This can lead to code that is not secure and could cause vulnerabilities in your applications.

Despite these concerns, there are many ways to ensure that your code is secure. One way is to use a static analysis tool, such as JSLint or ESLint. These tools will scan your code for potential security issues and help you fix them.

Another way to ensure that your code is secure is to use a framework, such as AngularJS or ReactJS. These frameworks provide built-in security features that will help to protect your application.

Vanilla JS vs Frameworks

Many different frameworks are available for JavaScript, such as AngularJS, ReactJS, and VueJS.

Each of these frameworks has its own benefits and drawbacks.

  • AngularJS is a popular framework used by many companies, such as Google, Netflix, and Upwork. It is easy to use and has a lot of features. However, it is also large and can be challenging to learn.

  • ReactJS is another popular framework used by companies like Facebook, Instagram, and Airbnb. It is smaller than AngularJS and easier to learn. However, it doesn't have as many features.

  • VueJS is a newer framework used by companies such as Laravel, Alibaba, and Baidu. It is smaller than both AngularJS and ReactJS and easier to learn. Additionally, it has many features.

Vanilla JS is a term used to describe JavaScript that is not written using a framework. This means that the code is written from scratch and is not based on any existing code.

Vanilla JS is a lightweight version of JavaScript that is easy to learn. It does not include any added libraries and is not customized. This makes it suitable for developing small applications, although large companies like Google, Apple, and Amazon also use it.

Vanilla JS is a great way to learn the JavaScript basics before familiarizing yourself with JavaScript libraries.

JavaScript libraries

Many different libraries are available for JavaScript, such as jQuery, Lodash, and Underscore. Essentially, they are collections of pre-written code that you can use to make developers' lives easier. With JavaScript libraries, you can animate elements on a page, make AJAX requests, and format data. Using a CDN with JavaScript Libraries

A CDN, or Content Delivery Network, is a network of servers used to deliver content to users. When you use a CDN with JavaScript libraries, the library files are downloaded from the CDN instead of from your own server.

This has several benefits. First, it reduces the load on your server as the files are downloaded from the CDN instead. Second, it speeds up the loading of your page as the files are downloaded from a server that is close to the user's location.

KeyCDN is a popular CDN that allows you to deliver your JavaScript assets in an accelerated way, which increases the performance of your website.

To use a CDN with your JavaScript libraries, you need to include the library files in your HTML code. For example, if you wanted to use the jQuery library, you would include the following code in your HTML:

<script src=""></script>


JavaScript is a programming language that is used to make web pages interactive. It is mainly run on the user's computer rather than on the server, making it predominantly a client-side language. There are many different libraries and frameworks available for JavaScript, each with its own benefits and drawbacks. Vanilla JS is a lightweight version of JavaScript that is easy to learn.

JavaScript is a versatile language that can create a wide variety of applications. Choosing the right tool for the job is important, as different tools are better suited for various tasks. With the right tool, you can create anything from a simple web page to a complex web application.

JavaScript is a great language to learn if you want to get into web development. It is easy to learn, and there are many resources available. Once you have learned the basics, you can explore the different available libraries and frameworks. With JavaScript, the sky is the limit!

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