YouTube Volume Mouse Controller

Control YouTube volume by mouse.
Versión del día 29/12/2018. Echa un vistazo a la versión más reciente.
Pregunta tus dudas, ponle nota o notifica una posible infracción de las normas.
Ajuste de línea
// ==UserScript==
// @name YouTube Volume Mouse Controller
// @namespace wddd
// @version 1.1.0
// @author wddd
// @description Control YouTube volume by mouse.
// @homepage https://github.com/wdwind/YouTubeVolumeMouseController
// @match *://www.youtube.com/*
// @require https://ajax.aspnetcdn.com/ajax/jQuery/jquery-3.3.1.min.js
// @grant GM_addStyle
// @noframes
// ==/UserScript==

function run() {
    "use strict";

    var player = $("video");
    var timer = 0;

    // detect available wheel event
    var support = "onwheel" in document.createElement("div") ? "wheel" : // Modern browsers support "wheel"
        document.onmousewheel !== undefined ? "mousewheel" : // Webkit and IE support at least "mousewheel"
            "DOMMouseScroll"; // let"s assume that remaining browsers are older Firefox

    player.bind(support, function(event) {
        var originalEvent = event.originalEvent;
        var volume = player[0].volume;
        var volumeDelta = 0.05;
        var deltaY = 0;

        if (support == "mousewheel") {
            deltaY = originalEvent.wheelDelta;
        } else {
            deltaY = originalEvent.deltaY || originalEvent.detail;
        }

        volume += (deltaY > 0 ? -volumeDelta : volumeDelta);
        player[0].volume = Math.max(0, Math.min(1, volume));

        $(".ytp-volume-panel").attr("aria-valuenow", (player[0].volume * 100).toFixed(0));
        $(".ytp-volume-slider-handle").css("left", ((player[0].volume * 100) * 0.4) + "px");

        showSlider();

        // Prevent the page to scroll
        return false;
    });

    function showSlider() {
        if (timer) {
            clearTimeout(timer);
        }

        var sliderBar = $("div#sliderBar");
        if (!sliderBar[0]) {
            $("body").append("<div id=\"sliderBar\"></div>");
            GM_addStyle([
                "#sliderBar {width: 100%;",
                "height: 20px;",
                "position: fixed;",
                "top: 63px;",
                "z-index: 9999;",
                "text-align: center;",
                "color: #fff;",
                "font-size: initial;",
                "opacity: 0.9;",
                "background-color: rgba(0,0,0,0.2);}",
            ].join(" "));
            sliderBar = $("div#sliderBar");
        }

        sliderBar.fadeIn(100);
        timer = setTimeout(function() {
            sliderBar.fadeOut(700);
        }, 1000);

        sliderBar.html("Volume: " + (player[0].volume * 100).toFixed(0));
    }
}

/**
 * YouTube use Javascript to navigate between pages. So the script will not work:
 * 1. If the script only includes/matches the sub pages (like the video page www.youtube.com/watch?v=...)
 * 2. And the user navigates to the sub page from a page which is not included/matched by the script
 *
 * In the above scenario, the script will not be executed.
 *
 * To run the script in all cases,
 * 1. Include/match the whole YouTube host
 * 2. Detect Javascript events, and run the script appropriately
 *
 * Details:
 * * https://stackoverflow.com/questions/32275387/recall-tampermonkey-script-when-page-location-changes/32277150#32277150
 * * https://stackoverflow.com/questions/34077641/how-to-detect-page-navigation-on-youtube-and-modify-html-before-page-is-rendered
 * * https://github.com/1c7/Youtube-Auto-Subtitle-Download/blob/master/Youtube-Subtitle-Downloader/Tampermonkey.js#L122-L152
 */

// trigger when loading new material design page
var body = document.getElementsByTagName("body")[0];
body.addEventListener("yt-navigate-finish", function() {
    if (window.location.href.includes("/watch?v=")) {
        run();
    }
});

// trigger when loading old page
window.addEventListener("spfdone", function() {
    if (window.location.href.includes("/watch?v=")) {
        run();
    }
});