JavaScript Validator
Validate JavaScript syntax. Check for errors without executing the code — all in your browser, no upload.
About the JavaScript Validator
This JavaScript validator runs entirely in your browser. Paste your code into the box above and click Validate to check its syntax. The tool uses the Function constructor to parse the code without executing it, so it is safe to test snippets that would otherwise have side effects.
How it works
- Validate — Constructs a function from your code (
new Function(code)). If the syntax is invalid, the browser throws aSyntaxErrorwith a message and (where available) a line and column number. - Format — Re-indents the code based on brace (
{ }) depth. This is a basic formatter that adjusts indentation only; it does not rewrite your statements. - Clear — Resets the input and result.
Limitations
Because the code is wrapped in a function body, top-level import/export statements and top-level await are not supported and will be reported as errors even though they are valid in modules. The line and column numbers come from the browser engine and may not be available in every browser.
Frequently asked questions
Does this tool execute my code? No. It only parses the code to check syntax. The constructed function is never called.
Does it upload my code? No. All parsing happens locally in your browser.
Why does it report an error for import? The Function constructor treats your input as a function body, where module syntax is not allowed. Paste regular script code for the most accurate results.