Toolbox for developers / JavaScript Online

JavaScript validator

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.

  • JavaScript
  • HTML
  • CSS



ECMAScript version



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.

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 tool uses JSHint library.

JavaScript fiddle

You can test your JavaScript code online directly in your browser.

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).


Disclaimer: The tools are provided "as is", without warranty of any kind, either express or implied.
Any links to third-party website or software available on this website are provided "as is",
without warranty of any kind, either express or implied and are to be used at your own risk.