Video Speed Buttons

Add speed buttons to any HTML5 <video> element. Comes with a loader for YouTube and Vimeo
当前为 2017-09-06 提交的版本，查看最新版本。
换行
// ==UserScript==
// @name         Video Speed Buttons
// @description  Add speed buttons to any HTML5 <video> element. Comes with a loader for YouTube and Vimeo
// @namespace    bradenscode
// @version      1.0.2
// @copyright    2017, Braden Best
// @run-at       document-end
// @grant        none
//
// @match        *://*.youtube.com/*
// @match        *://*.vimeo.com/*
// ==/UserScript==
 
// To add a new site: add a @match above, and modify loader_data.container_candidates near the bottom
 
function video_speed_buttons(anchor, video_el){
    if(!anchor || !video_el)
        return null;
 
    const COLOR_SELECTED = "black",
        COLOR_NORMAL = "grey",
        BUTTON_SIZE = "100%",
        DEFAULT_SPEED = 1.0,
        LABEL_TEXT = "Video Speed: ";
 
    const BUTTON_TEMPLATES = [
        ["25%",    0.25],
        ["50%",    0.5],
        ["Normal", 1],
        ["1.5x",   1.5],
        ["2x",     2],
        ["3x",     3],
        ["4x",     4],
        ["8x",     8],
        ["16x",    16]
    ];
 
    const buttons = {
        head:      null,
        selected:  null,
        last:      null
    };
 
    const keyboard_controls = [
        [",", "Speed Down", function(ev){
            if(is_comment_box(ev.target))
                return false;
 
            (buttons.selected || buttons.head)
                .getprev()
                .el
                .dispatchEvent(new MouseEvent("click"));
        }],
        [".", "Speed Up", function(ev){
            if(is_comment_box(ev.target))
                return false;
 
            (buttons.selected || buttons.head)
                .getnext()
                .el
                .dispatchEvent(new MouseEvent("click"));
        }],
        ["?", "Show Help", function(ev){
            var infobox;
 
            if(is_comment_box(ev.target))
                return false;
 
            (infobox = Infobox(container))
                .log("Keyboard Controls (click to close)<br>");
 
            keyboard_controls.forEach(function([key, description]){
                infobox.log("    [.s]  .s<br>"
                        .replace(".s", key)
                        .replace(".s", description)); });
        }]
    ];
 
    const container = (function(){
        var div = document.createElement("div");
        var prev_node = null;
 
        div.className = "vsb-container";
        div.style.borderBottom = "1px solid #ccc";
        div.style.marginBottom = "10px";
        div.style.paddingBottom = "10px";
        div.appendChild(document.createTextNode(LABEL_TEXT));
 
        BUTTON_TEMPLATES.forEach(function(button){
            var speedButton = SpeedButton(...button, div);
 
            if(buttons.head === null)
                buttons.head = speedButton;
 
            if(prev_node !== null){
                speedButton.prev = prev_node;
                prev_node.next = speedButton;
            }
 
            prev_node = speedButton;
 
            if(speedButton.speed == DEFAULT_SPEED)
                speedButton.select();
        });
 
        return div;
    })();
 
    function is_comment_box(el){
        return el === document.querySelector(".comment-simplebox-text");
    }
 
    function Infobox(parent){
        var el = document.createElement("pre");
 
        el.style.font = "1em monospace";
        el.style.borderTop = "1px solid #ccc";
        el.style.marginTop = "10px";
        el.style.paddingTop = "10px";
 
        el.addEventListener("click", function(){
            parent.removeChild(el);
        });
 
        parent.appendChild(el);
 
        function log(msg){
            el.innerHTML += msg;
        }
 
        return {
            el,
            log
        };
    }
 
    function setPlaybackRate(el, rate){
        if(el)
            el.playbackRate = rate;
        else
            console.log("setPlaybackRate: video element is null or undefined");
    }
 
    function SpeedButton(text, speed, parent){
        var el = document.createElement("span");
        var self;
 
        el.innerHTML = text;
        el.style.marginRight = "10px";
        el.style.fontWeight = "bold";
        el.style.fontSize = BUTTON_SIZE;
        el.style.color = COLOR_NORMAL;
        el.style.cursor = "pointer";
 
        el.addEventListener("click", function(){
            setPlaybackRate(video_el, speed);
            self.select();
        });
 
        parent.appendChild(el);
 
        function select(){
            if(buttons.last !== null)
                buttons.last.el.style.color = COLOR_NORMAL;
 
            buttons.last = self;
            buttons.selected = self;
            el.style.color = COLOR_SELECTED;
        }
 
        function getprev(){
            if(self.prev === null)
                return self;
 
            return buttons.selected = self.prev;
        }
 
        function getnext(){
            if(self.next === null)
                return self;
 
            return buttons.selected = self.next;
        }
 
        return self = {
            el,
            text,
            speed,
            prev:  null,
            next:  null,
            select,
            getprev,
            getnext
        };
    }
 
    function kill(){
        anchor.removeChild(container);
        document.body.removeEventListener("keydown", ev_keyboard);
    }
 
    function ev_keyboard(ev){
        let match = keyboard_controls.find(([key, unused, callback]) => key === ev.key);
        let callback = (match || {2: ()=>null})[2];
 
        callback(ev);
    }
 
    setPlaybackRate(video_el, DEFAULT_SPEED);
    anchor.insertBefore(container, anchor.firstChild);
    document.body.addEventListener("keydown", ev_keyboard);
 
    return {
        controls: keyboard_controls,
        buttons,
        kill,
        SpeedButton,
        Infobox,
        setPlaybackRate,
        is_comment_box
    };
}
 
video_speed_buttons.from_query = function(anchor_q, video_q){
    return video_speed_buttons(
            document.querySelector(anchor_q),
            document.querySelector(video_q));
}
 
// Multi-purpose Loader (defaults to floating on top right)
const loader_data = {
    container_candidates: [
        // YouTube
        "div#container.ytd-video-primary-info-renderer",
        "div#watch-header",
        "div#watch7-headline",
        "div#watch-headline-title",
        // Vimeo
        ".clip_info-wrapper",
    ],
 
    css_div: [
        "position:    fixed",
        "top:         0",
        "right:       0",
        "zIndex:      100",
        "background:  rgba(0, 0, 0, 0.8)",
        "color:       #eeeeee",
        "padding:     10px"
    ].map(rule => rule.split(/: */)),
 
    css_vsb_container: [
        "borderBottom:    none",
        "marginBottom:    0",
        "paddingBottom:   0",
    ].map(rule => rule.split(/: */))
};
 
setInterval(function(){
    let vsbc = () => document.querySelector(".vsb-container");
    let candidate;
    let default_candidate;
 
    if(document.readyState !== "complete" || vsbc() !== null)
        return;
 
    candidate = loader_data
        .container_candidates
        .map(candidate => document.querySelector(candidate))
        .find(candidate => candidate !== null);
 
    default_candidate = (function(){
        let el = document.createElement("div");
 
        loader_data.css_div.forEach(function([name, value]){
            el.style[name] = value; });
 
        document.body.appendChild(el);
        return el;
    }());
 
    video_speed_buttons(candidate || default_candidate, document.querySelector("video"));
 
    if(!candidate)
        loader_data.css_vsb_container.forEach(function([name, value]){
            vsbc().style[name] = value; });
}, 100);