My first impression was that it was useless, because it states file:// URLs aren't supported. The docs on GitHub talk mainly about Chrome and the video has no sound, so I didn't find the workaround that somebody else posted in a comment. Here's the fix: https://superuser.com/questions/696361/how-to-get-the-markdown-viewer-addon-of-firefox-to-work-on-linux/1175837#1175837

The fact that this isn't clear in the instructions seems a pretty scathing oversight.

Anyhow, once I added the MIME type, it started working pretty well.

It lacked a bit of detail to set the Markdown title to the tab's title when the file was loaded.

Rating 1 star because of permissions, this plugin should not require access to all data on all websites.

works great in chrome, but apparently does not support in firefox 77.0.1, i want to use this amazing dark themes in firefox, pls fix it

It's an excellant addon,but the support of printing page is poor .the page rendered by this plugin can not be printed completely.

这个扩展很好用，但是对打印的支持不尽如人意。这个插件渲染的页面无法被完整地打印。

Great, but Table of Contents sorely needs a dark option.

The same problem with the plugin on KDE. In spite of the [MIME solution by Firefox user 15126385](https://cup.aihedy.com/en-US/firefox/addon/markdown-viewer-chrome/reviews/1453572/) works perfectly, I have to refresh the page or change any of settings to see the content instead of blank page.

Plugin v. 3.8
Firefox v. 74.0

P.S. That solution for KDE should have appearance in the Documentation.

Markdown瀏覽器用的預覽工具,非常好用,多謝開發者.

Of all the markdown extensions I like the way this one looks the most. I'm bummed that it totally doesn't work.

Just getting file:// URLs to open in firefox is a huge pain. Whenever I open markdown files, Firefox just wants to download them. See here to fix: https://superuser.com/questions/696361/how-to-get-the-markdown-viewer-addon-of-firefox-to-work-on-linux/1175837#1175837
Edit: This isn't the fault of the extension

The way the superuser article fixes the problem involves making all markdown files part of the text/plain mimetype but other apps on KDE (and possibly other 'DEs) use the text/markdown mimetype differently than text/plain. So I went into about:config and changed helpers.private_mime_types_file to a custom file (e.g. ~/.firefox-mime.types) to separate firefox's mimetypes from the rest of my system. I then added "text/plain md markdown" in that file. The problem is due to the way firefox handles files and mimetypes.
Edit: Again, this isn't a problem with the extension but does make it tricky to set up.

With this extension, when I open a markdown page, about half the time I just get a blank white page and half the time I see the file. Whenever I enable markdown or change markdown settings, the page reloads and I almost always get back to the blank white page.

When I open the addon's settings page, there are some pretty bad graphical glitches, everything is squished together and the bottom border just keeps slowly inching farther and farther down my screen.

Still does not support file:// type. sad,

This addon does more than I expected it would. Being able to set a great variety of themes (incuded a dark one) is a great plus.

This add-on is a subsitution of https://cup.aihedy.com/zh-CN/firefox/addon/markdown-viewer/?src=search

Unfortunately, that author didn't maintain the add-on, but It can open markdown files in a Frame, this is the most important reason for I still stay on Firefox 56 and not upgrade to Firefox Quantum.

Simeon Velichkov's markdown-viewer is compatible with Firefox Quantum, But it can not display markdown in a Frame, can you solve this problem?

Good, but it doesn't correctly interpret code blocks for python