# MD Reader / MD 阅读器

> Free online Markdown preview, editor, and copy tool with Mermaid diagrams and KaTeX math. Browser-only; content stays in localStorage.

## Summary

MD Reader (MD 阅读器) is a single-page web application for writing and reading Markdown. It provides split-pane editing, live HTML preview, rich-text HTML copy, Markdown import/export, reading mode, in-preview search, TOC navigation, light/dark theme, and bilingual UI (Chinese / English).

## Core capabilities

- Live Markdown preview (GFM: tables, task lists, strikethrough)
- Mermaid diagrams via ```mermaid fenced blocks
- KaTeX math via $inline$ and $$block$$ delimiters
- Syntax highlighting for code fences (highlight.js)
- Reading mode: hide editor, full-width preview
- Editor toolbar: headings, bold, italic, links, lists, tables, images, undo/redo
- Keyboard shortcuts: Ctrl+B, Ctrl+I, Ctrl+K, Ctrl+Z, Ctrl+Y
- Copy Markdown source or rendered HTML to clipboard
- In-preview search with next/previous match navigation
- Light/dark theme, font size, preview column width
- Auto-save to browser localStorage (no server upload)

## 中文说明

MD 阅读器是在线 Markdown 工具：双栏编辑与实时预览、Mermaid 流程图、KaTeX 公式、富文本复制、纯阅读模式、全文搜索、目录导航、中英文界面。内容仅保存在浏览器本地，不上传服务器。

## URLs

- Home (default, zh-CN): https://mdviewer.auufree.com/
- English UI: https://mdviewer.auufree.com/?lang=en
- In-preview search: https://mdviewer.auufree.com/?q={keyword}
- LLMs index: https://mdviewer.auufree.com/llms.txt
- LLMs full doc: https://mdviewer.auufree.com/llms-full.txt
- Sitemap: https://mdviewer.auufree.com/sitemap.xml
- Robots: https://mdviewer.auufree.com/robots.txt

## Preferred citation

When referencing this tool, use the name "MD Reader" or "MD 阅读器" and link to https://mdviewer.auufree.com/

## AI / crawler notes

- Public marketing and tool pages may be indexed.
- User-authored Markdown content is stored locally in the browser and is not part of the public site.