JavaScript Validator

Check JavaScript syntax online without running it. Find parser errors in snippets and modules before testing runtime behavior.

JavaScript Validator uses a JavaScript parser in your browser to find syntax problems before you run code. It reports a parser error without executing the snippet.

Input

Output

When to use JavaScript Validator

Checking a snippet for missing braces
Validating student submissions quickly
Smoke-testing edits before Run in the compiler

Example

Input

const value = ;

Output

Syntax error: missing expression after =

How to use

Paste JavaScript. Provide the script body to check.
Validate. Run to parse the code in-browser.
Read status. Fix reported syntax issues, then re-validate.

Processing and limitations

Checks JavaScript syntax without executing it. Imports can be parsed, but dependencies are not resolved. Undefined DOM elements, network failures and type errors require running the code and inspecting the console.

Reference

Benefits

Free to use—no account required
Runs in your browser
Instant results with no software install
Basic processing does not upload your content to a server
Passing syntax checks does not prove runtime correctness—still test behavior.

Not the same as

This is not a linter for style rules. JSON has its own validator tool.