Question 1

How do I check JavaScript syntax errors online?

Accepted Answer

Paste your JavaScript code into the input area and click Validate. The tool uses the browser built-in JavaScript engine to parse your code and reports any syntax errors with precise line and column numbers.

Question 2

What JavaScript features are supported?

Accepted Answer

The tool validates against whatever your browser supports — this includes ES6 (let, const, arrow functions, destructuring), ES2020+ (optional chaining, nullish coalescing), async/await, classes, modules (import/export) and top-level await in modern browsers.

Question 3

Does this tool execute my JavaScript code?

Accepted Answer

No. The tool only checks syntax by attempting to parse the code with the Function constructor or new Function(). Your code is never actually executed, so there are no side effects, no network calls, and no risk of running malicious code.

Question 4

Is my JavaScript code sent to a server?

Accepted Answer

No. All validation happens entirely in your browser using the native JavaScript parser. Your code never leaves your computer.