18 Cool Tools to test Javascript, HTML, CSS, and SQL code online

The demands of the viewers and visitors are ever increasing and developers have to find newer and better ways of enticing them to stay online before such visitors decide to move away to browse another website. Nowadays, there are websites where you can test your JavaScript code or java code snippets flawless testing before integrating them into your main website code. This gives you confidence that you are programming on the right track. Let us examine 18 awesome tools/websites where you can test JavaScript Code online.


With Codepen, you can test and share JavaScript, CSS, HTML, and any flavor of those. Show off your latest creation and get feedback. Build a test case for that pesky bug. Find example design patterns and inspiration for your projects.



Plunker is an online community for creating, collaborating on and sharing your web development ideas.

  • Speed: Despite its complexity, the Plunker editor is designed to load in under 2 seconds.
  • Ease of use: Plunker's features should just work and not require additional explanation.
  • Collaboration: From real-time collaboration to forking and commenting, Plunker seeks to encourage users to work together on their code.


W3Schools is optimized for learning, testing, and training. Examples might be simplified to improve reading and basic understanding.


This is a powerful and effective, yet simple JavaScript code checker. You just need to cut and paste your JavaScript in the window provided and examine the output. The correct JavaScript will run in the window provided below.


With JSFiddle, you can test and share JavaScript, CSS, HTML, or CoffeeScript online. It is described as the playground for web developers and it helps to isolate bugs. Many frameworks are supported, and this is a tool that you can utilize in many ways. With JSFiddle, JavaScript developers can easily edit bugs. It is also possible to share the code on GitHub and displayed in the form of a new fiddle.


This is a static code analysis tool that is used for checking if JavaScript source code complies with the coding rules. Developed by Douglas Crockford, it is provided primarily as an online tool. However, there are command line adaptations as well.


JSBin is an HTML, JavaScript, and HTML playground. This is the ideal place for people who need to experiment, learn, or help friends with a problem. HTML and CSS are rendered live in the window next to the coding window. It is also possible to use keyboard shortcuts so that you can get around faster using this platform.

You can also open the CSS panel and try changing things yourself. The window update can be viewed live. JS Bin is an open source project that is available on GitHub with instructions on how to host it yourself. Developers can also get a custom skin and starting templates in case they are in the running workshops or are teaching to a much wider audience.


This is a community-driven open-source tool that detects errors as well as potential problems in JavaScript code, so that you can enforce your team’s coding conventions. This is a very flexible testing tool so that you can easily adjust it to your particular coding guidelines as well as in the environment that coding is expected in.

With JSHint, you can scan a program that is written in JavaScript and it reports commonly made mistakes as well as potential bugs. This potential bug can be syntax errors, implicit type conversion bugs, leaking variables, or others. At the most, only 15% or so of the programs that go through JSHint pass its checks, whereas the others find some red flags, such as bugs or potential problems.


This is an online JavaScript Editor that can be useful for editing JavaScript online. It presents a simple screen where you can post your JavaScript and run the code to ensure that your script is doing fine.


This is a HTML5, CSS3 & JavaScript editor that comes with real-time (live) preview. It is the ultimate playground for web designers and developers. Also, it is a wonderful tool to test, check, practice, and create new projects.

Code Beautify

Code Beautify is a project that helps you validate your JavaScript code according to the JavaScript rules. It helps you find out errors in your script, so that you can write the correct JavaScript.


JS Beautifier will reformat and re-indent bookmarklets, along with ugly JavaScript, unpack scripts that are, as well as de-obfuscate scripts that are processed by www. javascriptobfuscator.com. You can beautify javascript using JS Beautifier in your web browser, or in the command line using node.js or python.


Tool to ensure that your JavaScript code does not violate the specified coding standard (Idiomatic Style Manifesto or JQuery Core Style Guidelines); It is a node.js application that checks the JavaScript Code style consistency according to a provided coding style. One can define a custom coding style by using the described JSON notation or by using one of the predefined standards.

Lets Code JavaScript

For those who program in JavaScript will realize that besides its good parts and not-so-good parts, it requires test driven development. This is a technique for ensuring that your code does what you think it should do. TDD is a great way of catching a majority of programming errors. Although it’s not 100% perfect, it’s very good at catching JavaScript bugs. Letscodejavascript is a website that involves the use of TDD which JavaScript programmers can use.


Ideone is an online compiler as well as a debugging tool. It allows programmers to compile source code as well as execute it in online in more than 60 programming languages including JavaScript. You can choose a programming language, enter the source code along with the optional input data, and you are ready to begin. This website utilizes the Sphere Engine ™ technology, which allows you to execute programs on a remote server in a secure manner along with a complete runtime environment.


JSpretty is a JavaScript beautifier. It allows you to enter a messy, minified, or obfuscated JavaScript (JS) into the respective field, which it cleans up and makes pretty. Within the editor, you will also find helpful line-numbers as well as syntax editing. The website also presents you with line numbers and syntax highlighting. This is one of the best tools available for correcting your indentation, spacing, and other formatting mistakes, which can make your project a bit disorganized.

Dirty Markup

DirtyMarkup is a web-based interface that is used for cleaning dirty markup. You can paste HTML, CSS, or JavaScript code and obtain the cleaned file.


This is a syntax validator that checks for mistakes as well as editors. Unlike a typical code validator, this syntax validator does not bother about coding styles as well as formatting. For syntax errors, this sign will be shown in the left-side gutter of the editor screen. You can place the mouse cursor over that sign, so that it will bring up the error description in detail.

Source: Code Morning XYZ


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