csw-allow-midi.user.js

// ==UserScript==
// @name         CSW Allow MIDI
// @namespace    salembeats
// @version      1
// @description  .
// @author       Cuyler Stuwe (salembeats)
// @include      https://work.crowdsurfwork.com/tasks/*
// @grant        none
// ==/UserScript==

function main() {
    for(const iframe of document.querySelectorAll("iframe")) {
        if(!!iframe.getAttribute("allow")) {
            iframe.setAttribute("allow", iframe.getAttribute("allow") + ", midi");
        }
        else {
            iframe.setAttribute("allow", "midi");
        }
    }
}

main();