Drop a JavaScript file. Any size.
safe · secure · no server · works offline · fast
…or just start typing at the cursor.
safe · secure · no server · works offline · fast
…or just start typing at the cursor.
OmniViewer opens a JavaScript file right in your browser. Drop a
.js file and you get a formatted, syntax‑highlighted
view plus a small toolkit: a compressor, a
deobfuscator, an obfuscator, a
stats report, and the raw and hex views. There is no
upload and no server — the code is read directly by your browser, and
the heavy work runs in a background Web Worker so the page never freezes.
The viewer reads only the bytes it needs to paint the screen, so even a
20 GB bundle opens instantly and privately.
\x hex escapes so they’re no longer human‑readable.JavaScript was written by Brendan Eich at Netscape in 1995 — famously in about ten days — and shipped as “LiveScript” before being renamed to ride the popularity of Java (to which it is otherwise unrelated). It was handed to Ecma International for standardisation, and the language is defined by the ECMAScript specification, ECMA‑262, maintained by the TC39 committee. There is no single IETF RFC for the language itself, though pieces of its ecosystem are (for example JSON is specified in RFC 8259). The 2015 edition (ES2015 / “ES6”) was a turning point — classes, modules, arrow functions, template literals — and the standard has shipped a new edition every year since.
A tiny example of modern JavaScript:
const greet = (name) => `Hello, ${name}!`;
console.log(greet('world'));
| Aspect | JavaScript | TypeScript | Java | Rust |
|---|---|---|---|---|
| Typing | Dynamic, at runtime | Static, checked then erased | Static, nominal | Static, with inference |
| Runs on | Browsers & Node/Deno/Bun | Compiles to JavaScript | The JVM | Native machine code |
| Build step | None required | Compile to JS | Compile to bytecode | Compile to a binary |
| Memory model | Garbage collected | Garbage collected | Garbage collected | Ownership, no GC |
| Best known for | The web’s language | Safer large JS codebases | Enterprise & Android | Systems & performance |
| First released | 1995 | 2012 | 1995 | 2015 |
OmniViewer opens every file format; JavaScript is one of the formats with dedicated tooling, powered by the same viewing engine as fastjsonviewer.com and hugecsv.com.
No. OmniViewer is a static page with no server-side processing: your .js file is read directly by your browser, and every tab — formatting, compressor, deobfuscator, obfuscator and stats — runs locally in a Web Worker. The file never leaves your computer.
The raw and hex views are windowed — they read only the bytes needed to paint the screen — so they open files of effectively unlimited size, up to 20 GB and beyond; the engine behind them has been tested in-browser with a 40 GB file. The formatted view and the whole-file tools (compressor, deobfuscator, obfuscator, stats) transform the file in memory, so on very large files they work on a bounded prefix and tell you when they do. The parseability check above the view is skipped past a size threshold for the same reason.
The compressor shrinks a file by removing comments and unnecessary whitespace while preserving line breaks, so the code stays valid and behaves identically. The obfuscator goes further: it minifies and then rewrites every text string as \x hex escapes, so the strings are no longer human-readable — useful for making a file harder to skim, not for real security.
It beautifies minified or packed code — one statement per line, proper indentation, and string escapes decoded back to readable characters — which makes the vast majority of minified bundles readable again. It does not rename mangled variables back to their originals (that information is gone once a minifier discards it), and it works at the token level rather than fully parsing, so unusual code may need a second pass.
JavaScript the language is standardised as ECMAScript in the ECMA-262 specification, maintained by the TC39 committee at Ecma International — not as an IETF RFC. Related data formats do have RFCs; JSON, for instance, is defined in RFC 8259. OmniViewer has a dedicated JSON viewer too, at fastjsonviewer.com.
JavaScript is dynamically typed and runs directly in browsers and in Node with no build step. TypeScript adds static types and compiles down to JavaScript. Java is statically typed and runs on the JVM, and is common in enterprise and Android software. Rust is statically typed, compiles to native code and manages memory through ownership without a garbage collector, which suits systems and performance-critical work. The page above has a side-by-side table.
Brendan Eich created it at Netscape in 1995, reportedly in about ten days. It first shipped as LiveScript and was renamed JavaScript for marketing reasons; it is unrelated to Java. It was later standardised as ECMAScript, with the influential ES2015 (ES6) edition arriving in 2015 and a new edition every year since.