CodeDown Chrome Extension (MV3)

Add download buttons to code blocks across ChatGPT, Z.Ai, Gemini, LMArena, Kimi, Le Chat, Meta AI, Copilot, Grok, and LongCat. Save snippets as ready-to-use files and organize multiple downloads with an advanced management menu.

Supported Sites

• ChatGPT (chatgpt.com)
• Z.AI (chat.z.ai)
• Google Gemini (gemini.google.com)
• LMArena (lmarena.ai)
• Kimi (www.kimi.com)
• Le Chat / Mistral (chat.mistral.ai)
• Meta AI (www.meta.ai)
• Microsoft Copilot (copilot.microsoft.com)
• Grok (grok.com)
• LongCat (longcat.chat)

Installation

Load Unpacked Extension

1. Open Chrome and navigate to chrome://extensions/
2. Enable Developer mode (toggle in top-right corner)
3. Click "Load unpacked"
4. Select the codedown-extension folder
5. The CodeDown icon should appear in your extensions toolbar

Pin the Extension (Recommended)

1. Click the puzzle piece icon in Chrome's toolbar
2. Find "CodeDown" and click the pin icon

Usage

Individual Downloads

• Navigate to any supported AI chat site
• Code blocks will automatically have a Download button added
• Click the button to download that specific code snippet

Bulk Download Manager

Open the manager using any of these methods:

1. Keyboard shortcut: Alt+Shift+S
2. Extension popup: Click the CodeDown icon in the toolbar
3. Right-click menu: Right-click on the page and select "Open CodeDown Manager"

The manager lets you:

• View all code blocks on the current page
• Select/deselect individual blocks (Shift+click for range selection)
• Download selected blocks as a ZIP file

Verification & Testing

Quick Sanity Check

1. ✅ Extension loads without errors in chrome://extensions/
2. ✅ Icon appears in toolbar
3. ✅ Visit chatgpt.com and generate some code
4. ✅ Download buttons appear on code blocks
5. ✅ Press Alt+Shift+S to open the manager
6. ✅ Click a download button - file downloads with correct extension

View Logs

Content Script Logs:

1. Open DevTools on the AI chat page (F12)
2. Go to Console tab
3. Logs prefixed with [CodeDown] (only visible if DEBUG=true in content.js)

Service Worker Logs:

1. Go to chrome://extensions/
2. Find CodeDown and click "Service worker" link
3. DevTools opens for the background script
4. Logs prefixed with [CodeDown BG]

File Structure

codedown-extension/
├── manifest.json       # Extension manifest (MV3)
├── background.js       # Service worker (context menu, shortcuts)
├── content.js          # Main functionality (injected into pages)
├── styles.css          # Injected CSS styles
├── popup.html          # Extension popup UI
├── popup.js            # Popup logic
├── lib/
│   └── jszip.min.js    # JSZip library for ZIP creation
├── icons/
│   ├── icon16.png      # 16x16 icon
│   ├── icon48.png      # 48x48 icon
│   └── icon128.png     # 128x128 icon
└── README.md           # This file

Permissions Explained

• storage: Reserved for future settings (not currently used)
• contextMenus: Right-click "Open CodeDown Manager" option
• host_permissions: Required to inject content scripts on supported AI chat sites

Keyboard Shortcuts

Shortcut	Action
Alt+Shift+S	Open/close CodeDown Manager

You can customize this in chrome://extensions/shortcuts

Differences from Userscript Version

1. GM_registerMenuCommand → Context menu + popup + keyboard shortcut
2. ScriptNotifier → Removed (update notifications not needed for extensions)
3. GM_addStyle → CSS file injected via manifest
4. JSZip → Vendored locally in lib/ folder

Troubleshooting

Download buttons don't appear:

• Refresh the page
• Check that the extension is enabled
• Verify you're on a supported site

Manager doesn't open:

• Try the keyboard shortcut (Alt+Shift+S)
• Check for errors in the console
• Reload the extension

ZIP download fails:

• Check browser console for errors
• Ensure JSZip library loaded correctly

Credits

• Original userscript by OHAS
• Converted to Chrome Extension (MV3)

License

CC-BY-NC-ND-4.0