These are usually plug-in devices like audio synthesizers, but might also be built into your computer.  Websites are normally not allowed to access MIDI devices. Improper usage could cause damage or compromise security.
TE su zwjetša tykačowe graty kaž awdiosyntesizery, ale móža tež we wašim ličaku zatwarjene być.  Websydła w normalnym padźe přistup k MIDI-gratam nima. Wopačne wužiwanje móhło škodu zawinować abo wěstotu pomjeńšić.