JavaScript Support Checker
Fast, accurate, and free online JavaScript Support Checker tool that runs directly in your browser.
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1Enter data
Enter content, paste text or load a file from disk. -
2Click the button
The tool will immediately process your data in the browser. -
3Get the result
Copy the finished text or save the file to your device.
return "Result ready in 0.1s";
}
JavaScript diagnostics
Analysis of the script engine and browser capabilities
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You can check support for modern network standards with one click.
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Other tools you may find usefulChecking JavaScript support - online browser test (does JS work?)
Do you have the impression that the website is not clickable, forms are not sending, and buttons seem dead? This JavaScript checker will show you whether your browser executes scripts and what modern JS features are available. No guessing, no blindly entering settings - you just run the diagnostics and get a report.
"JavaScript enabled or disabled?" is a question that comes back like a boomerang - especially when a bank, store, login panel or video platform suddenly refuses to cooperate. The problem is that "enable JS" itself can be too general. Sometimes JavaScript is enabled, but it is blocked by an extension (e.g. NoScript / adblock), the browser works in restrictive mode, cookies are disabled, and the browser's memory (Local Storage) does not save data. Then the website looks broken, although it is simply missing one of the key building blocks.
This tool is designed to help you stop "shooting" in 30 seconds and start taking action. You get a set of information about the environment: whether cookies work, whether there is Local Storage and Session Storage, whether the browser supports Fetch API, Promise, Web Crypto API, WebAssembly (WASM), and even basic hardware metrics (CPU cores, estimated RAM) and screen parameters. For many web services, these are the elements that determine whether the web application will run.
What does the JavaScript test check?
After running the diagnostics, the tool collects data from the browser and arranges it into a readable report. The most important thing: whether JS is executed, but also whether you have access to the functions that modern websites use. In practice, it is a quickbrowser compatibility checkerand a test of whether your settings and extensions do not "cut off" important mechanisms.
If anything is blocked, you immediately see what: cookies, Local Storage, WebAssembly, Web Crypto, Fetch API. Thanks to this, you know whether the problem is in the settings, in browser add-ons, or in the browser itself (e.g. a very old version).
When is this really useful?
The most common scenario: "the website doesn't work", but no one wants to play with the console. Then the test gives you hard facts. It's also a great way to compare performance on different devices - e.g. computer vs. phone, Chrome vs. Firefox, private mode vs. normal.
If you contact support (bank, store, SaaS), a report in JSON form can shorten the conversation by half. Instead of "it works for me", you have something specific: "cookies = NO", "localStorage = NO", "webdriver = DETECTED" or "WASM = NO".
How to use the tool step by step
This is not a test that requires technical knowledge. You go in, click run diagnostics and that's it. If JavaScript is completely disabled, you will see a message right from the start - because some measurements cannot be performed without JS. If the test passes, you will get results in several sections: supported technologies, system metrics and browser identification.
- Run diagnostics (start button).
- Check the "Supported Technologies" section - this is usually where the source of the problem lies.
- If you report a problem to support, copy the JSON report and paste it into the ticket.
- If something is "NO", disable blocking extensions for a while or check your privacy settings and repeat the test.