doesn't work where there on embedded video or audio
doesn't work on private browsing
everywhere else works 100% for me

I was gladly surprised to see it work on Pocket Cast website.

Keep up the good work!

Working great on ArchLinux's Gnome, but would be gread if Mac OS X could be also supported.

Update for new VK design please

Une extension parfaite.

Like the developer, I was tired of switching tabs to play/pause when I had a full set of media keys on my keyboard. This extension allows me to control SoundCloud with ease and it works even when the Firefox window is not active.

I highly recommend this extension to anyone who uses media keys.

Я время от времени слушаю музыку через социальную сеть vkontakte и во время игровых сражений отвлекаться от игры для переключения нежеланного трека нет времени, этот аддон работает в directx приложениях, проще говоря при полном экране.
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Vkontakte - Worked & worked in full screen game, video etc.

Great

It works as expected when I have only one compatible site opened. Thanks!

When opening a second site I think the controls should then control the second site until it's closed.

Thanks dude. Does exactly what you would expect. Works with Google Play even when the tab or browser window is not active.

The missing-link in turning Firefox into a fully-fledged media-player. Also greatly appreciate the recently added support for the Plex web-player!

Прекрасное дополнение, давно искал что то подобное =)

Was looking for such add-on for quite some time. Good job.

I have UbuntuGnome 14.04 LTS (Linux), and I’ve been searching this kind of extensions activily for yeeeeears. Of course, it’s by chance I encounter it. A must have to play/pause music with your global OS media key for it. Thanks a million to the developer!

Sadly I have to shut down MS IntelliType using process explorer to make play/pause key on MS Natural Ergonomic Keyboard 4000 work, but I understand that's system limitation. Sadly without IntelliType most of the other multimedia keys don't work anymore, but since I listen music using browser only occasionally, this extension will suit my needs.

I am using it only with youtube, and it seems pretty reliable.

Good addon, but too little sites are supported. Is there any way to add other sites (i.e. via custom js scripts)? And, BTW, is this addon open source? If so, where can I find it?
UPDATE:
After all the updates it is perfect!

Nifty little extension. Works out of the box even on linux! (FF42)

Works exactly as described, installed without needing a reboot and within a few seconds I could press the play/pause button and my most recent YouTube tab would pause. It keeps track of which YouTube tab is most recent in case you have more than one open and only toggles the playing on that one tab. No problems with it not working when Firefox is out of focus like others have reported. Using a Microsoft Natural Ergonomic Keyboard 4000 v1.0.

I can't seem to get it to work with my Microsoft Sidewinder X4 Keyboard. The keyboard uses "Microsoft Mouse and Keyboard Center" for the programming of media keys and macros. I'm running Firefox Developer Version 44.0a2 (2015-11-25)

chance to redefine or disable other multimedia keyboard keys in Firefox like Browser_home, Browser_refresh, Browser_favorites etc.? I am looking for such solution, but no extension provides this functionality.

tested using spotify web player and youtube

Nice add-on.
Is there any chance to make this work on OS X?

does exactly what you want and need it to do.

Quick easy install and my media button (pause) works on sites like Youtube! Signed up to Mozilla for this review :)

edit: Currently doesn't work at all for Firefox 42.0 :(

edit: Turns out the issue is IntelliType which is installed with "Microsoft Mouse and Keyboard Center" (so if you haven't rebinded any of your additional keys then best to just uninstall this because it doesn't do anything)