JavaScript Validator

This tool checks JavaScript code for syntax errors using built-in browser validation. It instantly tells you if the code is valid and highlights any issues with helpful messages. You can paste or import JavaScript-like code (including function blocks), see validation results, and copy or export the output.

Paste your input above or import a file below.
No file chosen
Supported file types: .txt, .log, .md, .html, .htm, .css
Total characters: 0

How to Use:

  1. Paste or type your JavaScript into the Input JavaScript box.
  2. Or click Choose File to import code from a .txt, .md, .html, or similar plain text file.
  3. The tool runs validation as you type.
  4. If valid, the same code appears in the Validation Result box.
  5. If invalid, an error message appears, including the reason.
  6. Use Copy Output to copy valid code or Export to File to download it.
  7. Click Clear All to reset the input, output, and file name.

Example:

Input:

function add(a, b) {
  return a + b
}

Output:

javascriptCopy codefunction add(a, b) {
  return a + b
}

If input is invalid:

function () {
  console.log("Oops");

Validation Result:

Invalid JavaScript:
Unexpected token ')'

Common Use Cases:

This tool is ideal for checking whether copied or written JavaScript code blocks are syntactically valid. It’s useful for debugging inline scripts, validating code snippets before embedding, or catching typos in config scripts. Everything runs client-side for quick and secure feedback.

Useful Tools & Suggestions:

If you’re cleaning up scripts, JavaScript Minifier can help shrink things down once you’ve got valid code. And when you’re jumping between formats, JSON Validator is handy for double-checking the data side of your scripts too.

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