JS file viewer — open JavaScript files online
Drop a JS file into AnyFile and see it instantly — no upload, no sign-up, no software to install. Everything runs locally in your browser, so the file never leaves your device.
Open a JS file nowWhat is a JS file?
JavaScript is the programming language of the web — the only language browsers run natively. A .js file contains source code executed on web pages, in Node.js servers or in apps.
How to open a JS file online
- Open the AnyFile viewer — it loads instantly and even works offline after the first visit.
- Drag your JS file into the window, paste it with Ctrl/⌘+V, or click “Choose a file”.
- The file type is detected automatically from its actual content (magic bytes), not just the extension.
- The file is rendered immediately — processed 100% locally, with nothing sent to any server.
Why open JS files with AnyFile?
- No upload — the file never leaves your device.
- Free, with no registration and no installation.
- Works offline after the first visit.
- Detects the real file type by content, not just by extension.
- Nothing ever fails: any unreadable file falls back to a universal hex view.
100% private by design
AnyFile has no server and no upload endpoint. Your JS file is read with the browser’s File API and processed entirely on your device — open your browser’s network tab and verify that nothing leaves the page. It even keeps working with the network disconnected.
Technical details
| Full name | JavaScript Source Code |
|---|---|
| Extensions | .js, .mjs, .cjs |
| MIME type | text/javascript |
| Category | Source code |
| Tier | Free |
Frequently asked questions
Is it free to open JS files?
Yes. Opening JS files in AnyFile is completely free — no registration, no watermarks and no file-size tricks.
Is my JS file uploaded to a server?
No. There is no server. The file is read locally by your browser using the File API, and all processing happens on your device. Nothing is transmitted anywhere.
Do I need to install software to open a JS file?
No. AnyFile runs in any modern browser on any operating system — Windows, macOS, Linux, Android or iOS. Nothing to download or install.
What happens if my JS file cannot be displayed?
No file ever fails completely: if a dedicated preview is not possible, AnyFile falls back to a universal hex viewer that shows the raw bytes, the detected signature and the file’s structure.