JavaScript validator

  • JavaScript
  • HTML
  • CSS



ECMAScript version




JavaScript validator allows to test and validate JavaScript online, and find JavaScript errors easily and quickly. This JavaScript code checker tool highlights and allows to navigate between lines with syntax error. To check your code, you must copy and paste, drag and drop a .js file or directly type in the "JavaScript" online editor below, and click on "Check JavaScript syntax" button.

This tool also is a JavaScript fiddle, you can fill html, CSS and JavaScript editors in order to run your source directly in your browser. You can see the user guide to help you to use this JavaScript fiddle tool.

User guide

To check js syntax:

  • First, Drag and drop your JavaScript file or copy / paste your JavaScript text directly into the editor above.
  • Finally, you must click on "Check JavaScript syntax" button to display if there is an syntax error in your code.

To run and execute your JavaScript code in your browser, it is analogous to the check js syntax, except that you must click on "RUN fiddle" button.

To share your code, You must only click on "SHARE fiddle" button (And choice a password)!

JavaScript checker

JavaScript Validator Online tool allows to find syntax errors (lint). If a syntax error is detected, then the line in error is highlighted.

This linter allows to report stylistic errors, it can improve the quality of the code. It can also signal suspicious constructs, avoid mistakes, and potentially dangerous things.

This tool uses JSHint library.

JavaScript fiddle

You can test your JavaScript code online directly in your browser and share it!

You just have to share the URL of your fiddle in order to share it. Your JS fiddle will be accessible to everyone, do not save sensitive data! The password is only used to protect its modification.

Save fiddle
Your fiddle has been permanently saved and you (or anybody) can access with this link:
Choice a password to modify/delete this fiddle later (your fiddle will be accessible to everyone, do not save sensitive data!). Enter password to modify this fiddle. Enter password to delete this fiddle.
You can report a bug or give feedback by adding a comment (below) or by clicking "Contact me" link (at the top right hand corner of the page).


Rob Veldhuyzen van Zanten-2021-12-02 14:06
JavaScript Tester: Empty array elements require elision=true.

How to adjust code?

Fmuaddib-2022-03-01 02:45
I'm on my iPad and there is no way to select all code when I finished, to copy it back.
There is no "copy to clipboard" function.
No way to select more than the first line of code.
How I'm supposed to use this tool?