Embedded MidiFile player

This script uses midicube's player (MIDI.js's successor) (and their HTML, etc.) to make it easy to add a MIDI player for any file or base64 data. The script looks something like this:
<div id='putMeHere'>

<script src="../build/music21.debug.js" type="application/javascript"></script>
<script>
    const mp = new music21.miditools.MidiPlayer();
    const domEl = document.querySelector('#putMeHere');
    mp.addPlayer(domEl);
    mp.base64Load('data:audio/midi;base64,TVRoZAAAAAYAAAABAYBNVHJrAAAu3QD/UQMH0zQA/wM...');
</script>
Notice that multiple MidiPlayers can coexist on the same page, as demonstrated with the two players below.