MIDI Javascript: how to generate a single MIDI note in javascript without libraries?

I've been reading the documentation about Web Midi API and I tried to look at different websites about the topic. Is there a way of playing a midi sound without using fancy libraries and stuff? Let's say I just want to generate a single note: how do I access the midi module that is present on your local machine? Can anyone write a small snippet of code that plays a single note and that I can simply embed in the element?