Works as expected, I have some issues with editing the CSS but I ended up not caring as much.

Why was I prompted for save option when I open .md file even after installed this addon??

On Windows (8.1) this extension works impeccably. It is indispensable for markdown viewing around the web and on local files.

That being said, I had issues making it work on Ubuntu (21.10). None of the solutions on the README page seemed to work (although it did previously). Finally (after many hours) I found the culprit: the snap installation of Firefox. After removing this problematic snap installation and reinstalling Firefox via get-apt, it started working again.

If I had this extension on Windows only, then I'd give it 5 stars hands down. However, the lack of a streamline installation on Linux systems brings it down to 4 stars. Nonetheless, it is an excellent extension imperative for markdown files.

The syntax highlighting options are nice, but if you have an URL in a code block, the double-slash is interpreted as a JS comment.

Does not work if the .md extension is in upper case.

It took me a while to even get it to do anything. I would appreciate proper instructions on how to use the extension.

This is not a problem with this extension, rather with Firefox. Whenever I open markdown files in firefox, it just wants to download them. I ended up having to change the mimetype text/plain to also include the extensions .md and .markdown. See here: https://superuser.com/questions/696361/how-to-get-the-markdown-viewer-addon-of-firefox-to-work-on-linux/1175837#1175837

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 my system. I then added "text/plain md markdown" in that file. The problem is due to the way firefox handles files and mimetypes.

I am unable to change the code style in the markdown-viewer menu which is very frustrating, the markdown style does work.

It works. For those like me using Linux, you should read the README in https://github.com/KeithLRobertson/markdown-viewer/blob/master/README.md#installing-on-linux At first it seemed like it was a no go but after reading the docs and following the procedure, the extension works just fine.

This is pretty good and does what I want. You can open a a markdown (.md) file on your machine in Firefox. There are multiple ways to style the page.

By default a small enlargable box is top left and you can click on this to get 3 options.

The first allows you to switch between the default and GitHub markdown style. (no utf-8 on one?).

The second has a decent list of styles that would be good but this didn't work for me.

The final option is a button to download the file as HTML. This works though the HTML is rather messy as it has all the code and styling for the dropdown box. You can remove the dropdown box though in the app’s settings though then of course you can’t click it to save as HTML. However you can delete the excess code from the file if you want to, though it's an extra step.

At least three other ways exist to to style pages. One is to write custom styles in the text box on the apps settings page. This is good for default styles.

Another way is to link to an external CSS file (put the link at the bottom of the page otherwise it won't work properly). You can also use an embedded stylesheet anywhere on the page (between two style tags).

All in all this is a great little add-on. Loses a mark from me because the dropdown styles didn't work for some reason and the generated HTML was messy.

Great extension.
Please, can you add markdown type mime "text/markdown" support (https://tools.ietf.org/html/rfc7763).
Thanks

Add-on works fine on Linux for local .md files using the mime type mod.
But where do you make the equivalent change for Firefox on OS-X?

It just displays .md files. Plain and simple – exactly what I searched for (there are MD editors with far more bells and whistles, if you want to, this one is totally minimalist).
Unfortunately, Firefox (at least under openSUSE Linux) has an issue with the MIME type. The solution linked here solves it: https://github.com/KeithLRobertson/markdown-viewer/issues/2
Oh, and btw, it only works (for me) with UTF-16, not UTF-8 as long as you don't manually add it a BOM, which is somewhat unusual … (can be fixed with " sed -i '1s/^/\xef\xbb\xbf/' foo ")

Presque parfait !
Petits bémols:
1) Il faut remplacer les sauts de ligne Linux (LF) par des sauts de ligne Microsoft (CR/LF).
2) Le rendu HTML est parfois assez différent de ce qu'on obtient avec un convertisseur standard.
Mais le résultat est néanmoins très acceptable.