JavaScript Online Compiler
Last Updated : 05 May, 2025
The JavaScript (JS) Online Compiler and Editor is a free online tool providing an integrated development environment (IDE) for creating and executing JavaScript code. Whether you are a beginner looking to learn JavaScript or an experienced developer want to test snippets of code quickly, an online compiler is an essential tool. An online JavaScript compiler allows you to write, run, and test JavaScript code instantly without the need for setting up any local environment.
In this article, we will explore some popular online JavaScript compilers and why using an integrated online development environment (IDE).
JavaScript online compiler offers a platform for writing, compiling, and debugging the code. This Code Editor provides various features, like light and dark mode, copy code, reset, fullscreen mode, code formatting, run code, and generating URLs for sharing.
Why Use a JavaScript Online Compiler?
Online compilers and IDEs provide several advantages:
- No Setup Required: No need to install JavaScript compilers or configure environments locally. Just open the browser and start coding.
- Cross-Platform: Since these tools run in the cloud, they are platform-independent. Whether you're on Windows, macOS, or Linux, you can access the same interface.
- Quick Prototyping: Great for testing small code snippets, debugging, and experimenting with new concepts quickly.
- Collaboration: Many online compilers provide features for code sharing and real-time collaboration with teammates or communities.
- Educational Tools: Beginners can start learning JavaScript interactively, without dealing with any initial setup issues.
Popular Online JavaScript Compilers
Here are some well-known JavaScript online compilers and IDEs:
1. GeeksforGeeks JavaScript IDE
The GeeksforGeeks JavaScript IDE and HTML, CSS, and JavaScript code editors are excellent choice for developers looking for an integrated platform to write, test, and run JavaScript code. It is specifically designed to help learners and professionals improve their coding skills through practice.
Key Features
- Option to execute only JavaScript code.
- Write JavaScript, HTML, and CSS in separate panes.
- Real-time code execution.
2. JSFiddle
JSFiddle is one of the most widely used online editors for web development. It allows you to write JavaScript, HTML, and CSS together in a single environment and provides live previews of your code.
Key Features
- Write JavaScript, HTML, and CSS in separate panes.
- Integrates popular JavaScript libraries.
- Real-time code execution.
3. CodePen
CodePen is a social development platform designed for front-end designers and developers. It is a popular choice for sharing JavaScript demos, web animations, and creating interactive visualizations.
Key Features
- Live previews.
- Support for JavaScript, HTML, and CSS.
- Large community and easy sharing of "Pens" (code snippets).
Example: This example illustrates the JavaScript code inside an HTML file using a script tag for finding the sum of the two numbers.
Online JavaScript Compiler (Code Editor) Features
- Light and Dark Mode: The code editor features both light and dark modes, allowing you to switch between them with ease.
- Shortcuts: The code editor has the feature of Keyboard shortcuts there are various shortcuts that help you to write code faster.
- Reset: With, this feature you can reset your page without refreshing the page.
- Copy Code: This is a feature that lets the user copy their code and they can paste it anywhere they want.
- FullScreen Mode: In this feature, you can code on full screen and exit by pressing the ESC key.
- Format: This feature gives proper formatting of the code which helps the user to understand quickly and code look presentable.
- Run: With this feature, you can easily run your code on the same page so you don't need to jump from one page to another which helps to debug code easily will less distraction.
- Run+Generate URL: This is a powerful feature that provides you the feature to run code and gives you a URL with a one-click through which you can showcase your website project to anyone.
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