bbb-volume-slider.user.js

// ==UserScript==
// @name         BBB Volume Slider
// @website      https://code.fbi.h-da.de/istddmue2/bbb-volume-slider-userscript
// @version      0.1
// @description  Adds a volume slider
// @author       Daniel Müller
// @match        https://*.h-da.de/html5client/join*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    // Check if the volume slider exists
    if (document.getElementById("vs-container") != null) return;

    // Create the container
    let vsc = document.createElement("div")
    vsc.id = "vs-container"
    vsc.style.position = "absolute"
    vsc.style.top = "20px"
    vsc.style.right = "75px"

    // Create the actual slider
    let vs = document.createElement("input")
    vs.type = "range"
    vs.min = 1
    vs.max = 100
    vs.value = 30

    // Set the audio volume to default value. This needs to be delayed due to BBB audio stream stuff
    window.setTimeout(() => {
        document.getElementById("remote-media").volume = Math.pow(vs.value / 100.0, 2)
    }, 1000)

    vs.oninput = function() {
        document.getElementById("remote-media").volume = Math.pow(this.value / 100.0, 2)
    }

    vsc.append(vs)
    document.body.appendChild(vsc)

})();