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Allows hotkeys and media keys to control the Spotify web player from any tab
It's a bug by violentmonkey. I can't call setInterval(function () { ... }, 100) with Violentmonkey on Spotify. Also, with uBlock installed, not one script runs on spotify. So I focus from now on on Tampermonkey. It's for now the best alternative.
I switched to Tampermonkey and still no functionality under FF 57.0.4, if uBlock is enabled for Spotify. Disabling uBlock helps. Thank you!
No function - Firefox 57
I installed the script in a quite fresh profile of a Firefox 57 with Violentmonkey.
No function at all, no reaction on the key combinations.