Day 1 of JS30Xplore
Today's Topic:
- What is Javascript?
- Why do we use Javascript?
- How to set up a development environment for JS.
- Including JavaScript in HTML
- Writing the first "hello world" program in JS
- Running Your First Program
1. What is JavaScript?
JavaScript is a high-level, interpreted programming language.
It is one of the three core technologies of the World Wide Web, alongside HTML and CSS. JavaScript is used to make web pages interactive and dynamic.
It can also be used to develop web applications, mobile applications, and games.
JavaScript is a text-based language, which means that it is written in plain text files.
JavaScript code is then interpreted by a JavaScript engine, which is a software component that executes JavaScript code.
The JavaScript engine is typically built into a web browser, but it can also be found in other environments, such as servers and mobile devices.
JavaScript is a front-end programming language, which means that it is used to develop the user interface of a web application.
JavaScript can also be used to develop back-end web applications, which are the servers that power web applications.
However, JavaScript is most commonly used for front-end development.
2. Why Javascript is required?
JavaScript is indispensable in web development for its ability to introduce interactivity and responsiveness to web pages.
By running on the client side, it reduces server loads and enables dynamic content updates without full page reloads.
JavaScript also validates user input, accesses web APIs for additional functionality, supports asynchronous operations for seamless user experiences, and enhances websites with animations and interactive elements.
These capabilities make JavaScript a fundamental tool for creating modern web applications that engage users and deliver dynamic content.
3. Setting Up Your Development Environment
To get started with JavaScript, you'll need a development environment.
Here are the essential tools:
- Code Editor:
Use a code editor like Visual Studio Code, Sublime Text to write your JavaScript code.
- Web Browser:
Most modern browsers like Chrome, Firefox, or Edge are suitable for running JavaScript code.
4. Including JavaScript in HTML
JavaScript code can be included in an HTML document using the <script> tag. There are two primary ways to do this:
- Inline script
- External script
5. Writing Your First JavaScript Code
Let's write your very first JavaScript program:
a simple "Hello World" message.
console.log("Hello, world!");
The console.log() function is used to display output in the browser's console.
6. Running Your First Program
To run your JavaScript program:
- Save your HTML file.
- Open the HTML file in your web browser.
- Open the browser's developer console.
You can usually do this by right-clicking on the page and selecting "Inspect" or "Inspect Element," and then navigating to the "Console" tab.
You should see the "Hello, world!" message displayed in the console.

Congratulations! You've learned how to write your first JavaScript program and embarked on your JavaScript learning journey.
Tomorrow, we'll dive deeper into variables and data types.