JSFiddle
jsfiddle.net
JSFiddle - Code Playground
JSFiddle - Test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle.
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Edit fiddle
JSFiddle - Test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle.
React - JSFiddle
JSFiddle - Test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle.
TypeScript
JSFiddle - Test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle.
Factsheet
Available in English
Founder(s) Oskar Krawczyk, Piotr Zalewa
URL jsfiddle.net
Available in English
Founder(s) Oskar Krawczyk, Piotr Zalewa
URL jsfiddle.net
W3Schools
w3schools.com › js › js_quiz.asp
JavaScript Quiz Test
You can test your JavaScript skills with W3Schools' Quiz.
Videos
16:57
Beginner’s Guide to JavaScript Testing and its Best Practices ...
JavaScript Unit Testing Tutorial for Beginners
Can you test JavaScript without a build step!?!
06:50
Jest Tutorial: Start with Unit Testing in JavaScript & Write Better ...
03:40
JavaScript Regex: Mastering the test() Method for Beginners - YouTube
02:51
JavaScript Regular Expressions: Using the Test Method | FreeCodeCamp ...
Noob Question: How do I "run" or test JS files like with Python or HTML/CSS?
So if you are writing JS code to be run in the browser, link your js file to your html file using the script tag and open the html file in the browser. If you are writing JS to run your computer/server you will need to install Node.js which is a JavaScript runtime environment. You can then run the file with node yourFile.js in the terminal. More on reddit.com
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February 18, 2022How to quickly test some javascript code? - Stack Overflow
What would be a good way to test Javascript on a browser? Should there be a localhost in my computer? and how to create one? More on stackoverflow.com
Free online tool to test out javascript?
Codepen, jsfiddle and the browser itself More on reddit.com
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March 5, 2025Headless CMS Performance Test - Payload vs. Directus vs. Strapi
Thank you for what you are doing! I've used strapi before and I think, that their documentation and permission setup (which is stored in database) is terrible. I would love to see your project compared to KeystoneJS. As it really is your only competitor. More on reddit.com
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September 28, 2022What is a JavaScript compiler?
A JavaScript compiler transforms your JavaScript code into optimized, executable code. Unlike traditional compilers that produce machine code, online JavaScript compilers and editors like PlayCode bundle your code, resolve imports, and transpile modern syntax (ES2026, TypeScript, JSX) into browser-compatible JavaScript that runs instantly. You can compile and edit JavaScript online with zero setup using our JavaScript editor.
playcode.io
playcode.io › javascript-compiler
JavaScript Compiler Online - Run JS Code Free | PlayCode
How fast is the online JavaScript compiler?
PlayCode's JavaScript compiler online is optimized for speed. When you run JavaScript online, initial compilation takes 100-500ms depending on project size. Incremental builds complete in 20-50ms. The fastest way to compile JavaScript online. That's often faster than running a local Node.js bundler because everything runs in memory with no disk I/O.
playcode.io
playcode.io › javascript-compiler
JavaScript Compiler Online - Run JS Code Free | PlayCode
Does the JavaScript compiler work offline?
Yes, you can run JavaScript online even offline once the page is loaded. The compiler runs entirely in your browser using WebAssembly, so you can keep coding and compile JavaScript without an internet connection. Your code is saved locally and syncs when you're back online.
playcode.io
playcode.io › javascript-compiler
JavaScript Compiler Online - Run JS Code Free | PlayCode
CodeBurst
codeburst.io › testing-your-javascript-code-95c171c71647
Testing your JavaScript Code. I know what you might be thinking… | by Johann Schuster | codeburst
December 3, 2017 - Testing your JavaScript Code I know what you might be thinking, there are so many languages and frameworks to learn, and so little time. Why should I spend more time on writing tests if my code seems …
CodeChef
codechef.com › skill-test › javascript
JavaScript Online Test & Quiz
Take the JavaScript Online Test & Quiz assessment to evaluate practical skills effectively using a set of well-designed, high-quality questions.
Playcode
playcode.io › javascript-compiler
JavaScript Compiler Online - Run JS Code Free | PlayCode
December 17, 2025 - Run JavaScript online to debug algorithms and test code snippets with detailed console output.
Reddit
reddit.com › r/learnjavascript › noob question: how do i "run" or test js files like with python or html/css?
r/learnjavascript on Reddit: Noob Question: How do I "run" or test JS files like with Python or HTML/CSS?
February 18, 2022 -
Hi all!
Learning HTML/CSS/JS, currently on JS. This is a very noob question, but how do I test run javascript code (for eg, a plotly graph or any function) in Visual Studio Code?
For example, with Python, I can just open it in an .ipynb and run a cell block to see the results. With HTML/CSS, I can open that file in VSC, then open in with "Live Server" or "Default Browser" extension to see a test webpage of it. Saving/refreshing the .html or .css file will reflect changes on my webpage.
Now, how do I do this with JS? I know about the inspect -> console, but that is to do print statements to the console or do math calculations. How do I "test run" graphs? Where do I even see those graphs?
Thanks.
W3Schools
w3schools.com › js › js_editor.asp
JavaScript Online Editor
With our online JavaScript editor, you can edit HTML, CSS and JavaScript code, and view the result in your browser.
TypeScript
typescriptlang.org › play
TypeScript: TS Playground - An online editor for exploring TypeScript and JavaScript
The Playground lets you write TypeScript or JavaScript online in a safe and sharable way.
MDN Web Docs
developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Global_Objects › RegExp › test
RegExp.prototype.test() - JavaScript | MDN
The test() method of RegExp instances executes a search with this regular expression for a match between a regular expression and a specified string. Returns true if there is a match; false otherwise. JavaScript RegExp objects are stateful when they have the global or sticky flags set (e.g., ...
Web-platform-tests
web-platform-tests.org › writing-tests › testharness.html
JavaScript Tests (testharness.js) — web-platform-tests documentation
JavaScript tests are the correct type of test to write in any situation where you are not specifically interested in the rendering of a page, and where human interaction isn’t required; these tests are written in JavaScript using a framework called testharness.js.
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Following is a free list of tools you can use to check, test and verify your JS code:
- Google Code Playground
- JavaScript Sandbox
- jsbin
- jsfiddle
- pastebin
- jsdo.it
- firebug
- html5snippet.net
Hope this helps.
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If you want to edit some complex javascript I suggest you use JsFiddle. Alternatively, for smaller pieces of javascript you can just run it through your browser URL bar, here's an example:
javascript:alert("hello world");
And, as it was already suggested both Firebug and Chrome developer tools have Javascript console, in which you can type in your javascript to execute. So do Internet Explorer 8+, Opera, Safari and potentially other modern browsers.
Codecademy
codecademy.com › forum_questions › 54b8c947d3292f61eb00494e
How can i use Javascript program for test on my local computer? | Codecademy
<!DOCTYPE html> <html> <head> <script type="text/javascript" src="script.js"></script> </head> <body> </body> </html>
MDN Web Docs
developer.mozilla.org › en-US › docs › Learn_web_development › Core › Scripting › Test_your_skills
Test your skills: JavaScript - Learn web development | MDN
August 18, 2025 - This page lists JavaScript tests you can try so you can verify if you've understood the content in this module.
Jest
jestjs.io
Jest · 🃏 Delightful JavaScript Testing
Jest is a delightful JavaScript Testing Framework with a focus on simplicity.
RunJS
runjs.app › play
Online JavaScript Playground
An easy-to-use online JavaScript playground with live feedback. Write and run JavaScript instantly. Great for learning and prototyping.
MDN Web Docs
developer.mozilla.org › en-US › docs › Learn_web_development › Extensions › Testing
Testing - Learn web development | MDN
April 11, 2025 - When we find the time, we are intending to update the material to cover General testing fundamentals, Functional and compat testing, and Usability testing. Before starting this module, You should really have learnt the fundamentals of HTML, CSS, and JavaScript.
W3Schools
w3schools.com › jsref › jsref_regexp_test.asp
JavaScript RegExp test() Method
regexp.test() is an ECMAScript1 (JavaScript 1997) feature. It is supported in all browsers: ❮ Previous JavaScript RegExp Methods Next ❯ · ★ +1 · Sign in to track progress · REMOVE ADS · PLUS · SPACES · GET CERTIFIED · FOR TEACHERS · BOOTCAMPS · CONTACT US ·
Medium
medium.com › @jamischarles › what-is-a-test-in-javascript-3d52cc3cd1a6
What is a Test in JavaScript?. I remember watching a talk on testing… | by Jamis Charles | Medium
July 14, 2018 - A test in JS or any programming language verifies the correctness of something.
Reddit
reddit.com › r/learnjavascript › free online tool to test out javascript?
r/learnjavascript on Reddit: Free online tool to test out javascript?
March 5, 2025 -
Hi guys
I'm looking for a free online tool where I can practice HTML, CSS and Javascript. I prefer something with an console included so that I can see my error messages right away. playcode.io is pretty great, but requires a subscribtion if you write more than a certain amount of code. Do you known of other similar solutions where I can see the console as well? I've been using https://onecompiler.com/ which lacks the console : (
Thanks!
Regex101
regex101.com
regex101: build, test, and debug regex
Regular expression tester with syntax highlighting, explanation, cheat sheet for PHP/PCRE, Python, GO, JavaScript, Java, C#/.NET, Rust.