FileView — Syntax Highlighter Extension

Instant syntax highlighting, code folding, and theme switching for any file you open in Chrome, Edge, or Firefox.

Download on Edge using:-

https://microsoftedge.microsoft.com/addons/detail/fileview-%E2%80%94-syntax-highlig/kpkhgfkppleimialngibfnehhifijlnm

Quick Start

Chrome / Edge

1. Open chrome://extensions (or edge://extensions)
2. Enable Developer mode (top-right toggle)
3. Click Load unpacked → select this folder
4. Click Details on the FileView card
5. Enable Allow access to file URLs
6. Open any local file with Ctrl+O or drag-and-drop

Firefox

1. Use manifest_firefox.json — rename it to manifest.json (back up the original first)
2. Open about:debugging → This Firefox → Load Temporary Add-on
3. Select the manifest.json file
4. May also need: about:config → set privacy.file_unique_origin = false

Safari

Requires Xcode conversion. See the onboarding page for full steps.

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Features (Phase 1)

Feature	Details
Syntax highlighting	80+ languages, auto-detected from file extension
Code folding	Click gutter arrows, or Fold All / Unfold from toolbar
9 Themes	Monokai, Dracula, Tomorrow Night, Solarized Dark, Twilight, GitHub, Chrome, Tomorrow, Solarized Light
Font size control	− / + buttons in toolbar, range 8–32px
Word wrap toggle	Toggle in toolbar
Search	Ctrl+F opens Ace search panel with regex
Status bar	Line count, language, cursor position
Large file protection	Files >2MB load first 5000 lines; option to load full file
Settings persistence	Theme, font size, word wrap saved via chrome.storage
Multi-browser	Chrome (MV3), Edge (MV3), Firefox (MV2)
JSON prettify	One-click formatting for JSON, XML, SQL, and more
Markdown preview	Live split/preview, fullscreen, KaTeX, Mermaid

Supported Languages

JS/TS/JSX/TSX · HTML/CSS/SCSS · Python · Java · Rust · Go · C/C++ · C# · Kotlin · Swift · Ruby · PHP · Lua · JSON · YAML · TOML · XML · SQL · Shell/Bash · Markdown · Dockerfile · Makefile · INI/CFG · Diff/Patch · CSV · CoffeeScript

File Structure

FileView-Syntax-Highlighter/
├── .github/
│ └── workflows/
│ └── release.yml
├── assets/
│ ├── 1.png
│ ├── 2.png
│ ├── 3.png
│ └── 4.png
├── dist/
│ └── ace-bundle.js
├── icons/
│ ├── icon128.png
│ ├── icon16.png
│ └── icon48.png
├── LICENSE
├── manifest_firefox.json
├── manifest.json
├── README.md
└── src/
├── ace-bundle-entry.js
├── background/
│ └── background.js
├── content/
│ ├── content.css
│ └── content.js
├── onboarding/
│ ├── onboarding.html
│ └── onboarding.js
└── popup/
├── popup.html
└── popup.js

Known Limitations (Phase 2+)

• No file editing — Chrome extensions can't write to disk directly. Phase 3 will add Native Messaging for save support.
• Git diff view — planned for Phase 2