Markdown Editor

Real-time markdown editor built with vanilla JavaScript. No frameworks, no dependencies.

Features

• Live Preview — Split-pane editor with draggable resizer
• Web Worker — Markdown parsing runs off the main thread
• XSS Sanitization — DOM-based allowlist strips dangerous tags, event handlers, and javascript: URLs
• Debounced Rendering — Custom debounce limits re-renders during fast typing
• Performance Monitoring — Render time measured with performance.now()
• Keyboard Shortcuts — Ctrl+B for bold, more to come

Tech

Vanilla HTML, CSS, JavaScript. Web Workers API. No build tools.

Run

python3 -m http.server 8080
# open http://localhost:8080

Supported Markdown

Headings (#, ##, ###), bold, italic, inline code, code blocks, [links], images, blockquotes, horizontal rules, lists.