Markdown Viewer Enhanced

Tracking since Apr 17, 2026.

Changelog

• Apr 27, 2026
  description

  A browser extension that elegantly renders Markdown files with Mermaid diagrams, syntax highlighting, KaTeX math formulas, table of contents navigation, multiple themes, and more.
  
  ## ✨ Key Features
  
  ### 🎨 Multiple Themes & Code Highlighting
  - **Three page themes** — Light / Dark / Auto (follows system preference)
  - **14 code highlight themes** — GitHub, Monokai, VS 2015, Atom One Dark, Dracula, Nord, Tokyo Night, and more
  - Code theme can be set to "follow page theme" for automatic switching
  
  ### 📊 Mermaid Diagram Rendering
  - Full support for Mermaid syntax: flowcharts, sequence diagrams, Gantt charts, class diagrams, state diagrams, and more
  - Diagrams automatically adapt their color scheme to the current page theme
  - **Click to zoom** — open diagrams in a fullscreen overlay with mouse wheel zoom, drag-to-pan, and keyboard shortcuts (`+` / `-` / `0`)
  - One-click "fit to window" and "reset zoom" controls
  - Copy Mermaid source code with a single click
  
  ### 💻 Enhanced Code Blocks
  - Powered by highlight.js with **180+** supported programming languages
  - Code blocks display a **language label** and a **one-click copy** button
  - Optional **line numbers** for easy code referencing
  - Code highlight theme is independent of page theme — use dark code themes on light pages
  
  ### 🔢 KaTeX Math Formulas
  - Supports LaTeX **inline** (`$...$`) and **block-level** (`$$...$$`) formulas
  - High-performance rendering powered by KaTeX with automatic CDN font loading
  - Smart detection to distinguish math formulas from currency symbols
  
  ### 📑 Table of Contents Navigation
  - Automatically generates a **TOC tree** from document headings
  - Supports **left / right** sidebar layout
  - Click any TOC item to **smooth-scroll** to the corresponding section
  - Current reading position is **automatically highlighted** and tracked in real time
  - Toggle the TOC sidebar on or off at any time

  # Markdown Viewer Enhanced
  
  > This document contains the English copy for the Chrome Web Store / Edge Add-ons listing page.
  
  ---
  
  ## Short Description (132 chars max)
  
  ```
  Render Markdown beautifully in your browser — with diagrams, code highlighting, math, TOC, themes, file browser, and more.
  ```
  
  ---
  
  ## Detailed Description
  
  **Markdown Viewer Enhanced** turns your browser into a powerful, beautiful Markdown reader. Open any `.md` file — local or remote — and it's instantly rendered with rich formatting, diagrams, syntax highlighting, and a full table of contents.
  
  ### 🎯 Why This Extension?
  
  Most Markdown viewers only handle basic formatting. **Markdown Viewer Enhanced** goes further — it supports Mermaid flowcharts, PlantUML diagrams, Graphviz graphs, KaTeX math formulas, 15+ code themes, and a built-in file browser for navigating local directories. All in a clean, customizable interface with light and dark themes.
  
  ---
  
  ### ✨ Features
  
  **📁 File Browser Sidebar**
  Browse your local file system with a directory tree. Expand/collapse folders, open files in new tabs, and navigate with breadcrumbs — all without leaving the browser.
  
  **🎨 Multiple Themes**
  Choose from Light, Dark, or Auto (follows your system). Pick from 15 code highlighting themes including popular choices like GitHub, Monokai, Dracula, and more.
  
  **📊 Mermaid Diagrams**
  Render flowcharts, sequence diagrams, Gantt charts, pie charts, and more. Click any diagram to zoom in with drag & pan support and keyboard shortcuts.
  
  **🌱 PlantUML Diagrams**
  Render UML class diagrams, sequence diagrams, activity diagrams, and more via the PlantUML online server. Click to zoom in a lightbox.
  
  **🔗 Graphviz (DOT) Graphs**
  Render DOT language graphs locally using the built-in Viz.js WASM engine. Click to zoom with a scale control bar — no external server needed.
  
  **💻 Syntax Highlighting**
  Powered by highlight.js with support for 180+ programming languages. Includes line numbers, one-click copy, and diff syntax highlighting.
  
  **🔢 Math Formulas (KaTeX)**
  Write inline math with `$...$` and display math with `$$...$$`. Full LaTeX formula rendering powered by KaTeX.
  
  **📑 Table of Contents (TOC)**
  Auto-generated heading tree with fold/expand support. Place it on the left or right sidebar. Scroll tracking highlights the current section, and URL hash navigation lets you link directly to any heading.
  
  **📐 Typography Controls**
  Fine-tune your reading experience: adjust font size, line height, content width, and font family. Drag to resize the sidebar to your preferred width.
  
  **🖼️ Image Lightbox**
  Click any image to zoom in. Scroll-wheel zoom (0.1x–20x), drag to pan, double-click to reset. Keyboard shortcuts: `+`/`-` to zoom, `0` to fit, `R` to reset, `Esc` to close. Zoom percentage indicator included.
  
  **📝 Extended Markdown Syntax**
  - GitHub-style alerts (`NOTE`, `TIP`, `IMPORTANT`, `WARNING`, `CAUTION`)
  - Task lists / checkboxes
  - Footnotes
  - Definition lists
  - Enhanced tables
  - `==highlight==`, `^superscript^`, `~subscript~`, `++underline++`
  - `:emoji:` GitHub-style emoji shortcodes
  
  **🔄 File Change Detection**
  Working on a Markdown file? The extension auto-detects when the source file changes and shows a pulsing "File updated" badge. Click to reload instantly.
  
  **⚙️ Flexible Settings**
  Quick-access popup panel for common settings, plus a full Options page for advanced customization. Changes push to all open tabs in real time.
  
  **🌐 Multi-Language Interface**
  Switch between English and Chinese (中文) in settings. The entire UI — popup, settings panel, options page — adapts to your language choice.
  
  ---
  
  ### 📋 Supported File Formats
  
  | Extension    | Description              |
  |-------------|--------------------------|
  | `.md`       | Markdown                 |
  | `.mdc`      | Markdown Component       |
  | `.markdown` | Markdown                 |
  | `.mkd`      | Markdown                 |
  | `.mdown`    | Markdown                 |
  | `.mdtxt`    | Markdown Text            |
  | `.mdtext`   | Markdown Text            |
  
  Local files (`file://`) support all extensions above. Remote files (`http://` / `https://`) support `.md`, `.mdc`, and `.markdown`.
  
  ---
  
  ### 🚀 Getting Started
  
  1. **Install** the extension from the Web Store
  2. **Open** any `.md` file in your browser
  3. **Enjoy** — the extension detects and renders Markdown automatically
  4. **Customize** — click the extension icon to adjust themes, fonts, and more
  
  #### 📂 Local File Access
  
  To render local Markdown files, enable file access:
  
  1. Go to `chrome://extensions/` (or `edge://extensions/`)
  2. Find **Markdown Viewer Enhanced** → click **Details**
  3. Enable **"Allow access to file URLs"**
  
  > 💡 **Tip**: The latest version is always available on [GitHub](https://github.com/LetitiaChan/markdown_viewer_enhanced). Web Store reviews may take time, so for the newest features, you can install via Developer Mode — download the source and load it as an unpacked extension.
  
  ---
  
  ### 🔒 Privacy & Permissions
  
  - **Does NOT collect** any user data
  - **Does NOT track** browsing activity
  - **Does NOT send** information to external servers (except PlantUML diagram rendering via plantuml.com and KaTeX font loading via CDN)
  - All settings are stored locally in your browser (`chrome.storage.sync`)
  - **Permissions used**:
    - `activeTab` — to detect and render Markdown on the current tab
    - `storage` — to save your preferences
    - `scripting` — to support the local file browser feature
  
  ---
  
  ### 🛠️ Powered By
  
  - [Marked.js](https://github.com/markedjs/marked) — Markdown parsing
  - [Mermaid](https://github.com/mermaid-js/mermaid) — Diagram rendering
  - [highlight.js](https://github.com/highlightjs/highlight.js) — Syntax highlighting
  - [KaTeX](https://github.com/KaTeX/KaTeX) — Math formula rendering
  - [Viz.js](https://github.com/nicknisi/viz.js) — Graphviz rendering (local WASM)
  - [DOMPurify](https://github.com/cure53/DOMPurify) — HTML sanitization for security
  
  ---
  
  ### 📬 Feedback & Support
  
  Found a bug? Have a feature request? We'd love to hear from you!
  
  - 🐛 [Report Issues on GitHub](https://github.com/LetitiaChan/markdown_viewer_enhanced/issues)
  - ⭐ If you find this extension useful, please leave a rating — it helps others discover it!
  
  ---
  
  *Markdown Viewer Enhanced — Make Markdown reading elegant.* ✨

• Apr 27, 2026
  short_description

  Render Markdown in your browser with Mermaid diagrams, syntax highlighting, TOC navigation, multiple themes, and more.

  在浏览器中渲染 Markdown 文件，支持 Mermaid 图表、语法高亮、目录导航、多主题等功能。

Permissions & access

Permissions

activeTabstoragescripting

Host access

None declared

Screenshots