Introducing Markdeep: A Lightweight JavaScript‑Based Markdown Editor with Extended Features

Markdeep is a pure‑text plugin that renders Markdown syntax directly in the browser, while also supporting extended capabilities such as charts, mathematical equations, and slide‑style presentations.

The tool works without any installation or network connection; adding the line <!-- Markdeep: --> at the end of a plain‑text file instantly converts it into a fully featured Markdown document.

Its source code is available as the single JavaScript file markdeep.js , which defines all formatting and rendering rules. The author continues to optimise the script size and add new features.

<code>&lt;!-- Markdeep: --&gt;
<style class="fallback">body{visibility:hidden;white-space:pre;font-family:monospace}</style>
<script src="markdeep.min.js" charset="utf-8"></script>
<script src="https://casual-effects.com/markdeep/latest/markdeep.min.js" charset="utf-8"></script>
<script>window.alreadyProcessedMarkdeep||(document.body.style.visibility="visible")</script>
</code>

To enable Unicode characters, prepend the document with <meta charset="utf-8"> . The resulting file should be saved with the .md.html extension.

Markdeep can be used for a wide range of documents, including API documentation, teaching outlines, game design files, homework, course PPTs, software library sites, personal blogs, resumes, and academic papers.

Examples demonstrate typical Markdown features—task lists, auto‑links, tables, inline images, and code blocks—plus LaTeX math rendering, all without extra plugins. The rendered output can be previewed instantly by refreshing the browser.

The project is open‑source; the latest script can be downloaded from https://casual-effects.com/markdeep/latest/markdeep.js . Although it is a hobby project with no formal support, the author responds to specific bug reports and regularly adds new features.