My custom userscript for changing the tab name while watching a youtube video.

userscript.js

// ==UserScript==
// @name         YouTube Timestamp Tab Name
// @version      0.1
// @description  Changed the tab name to contain the playing status and duration
// @match        https://www.youtube.com/watch*
// @author       123DMWM
// @grant        none
// @run-at       document-idle
// @require      http://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.js
// ==/UserScript==
(function() {
    'use strict';
    var ytplayer = document.getElementById("movie_player");
    const intervaltitle = setInterval(function() {
        var newTitle = getPlayPause(ytplayer) + " [" + getTimeStamp(ytplayer.getCurrentTime()) + "/" + getTimeStamp(ytplayer.getDuration()) + "] " + $("a.ytp-title-fullerscreen-link").text();
        if (!(document.title === newTitle)){
            document.title = newTitle;
        }
    }, 250);
    function getTimeStamp(SECONDS){
        return new Date((SECONDS * 1000) / ytplayer.getPlaybackRate()).toISOString().substr(11, 8).replace(/^[0:]{0,4}/,'');
    }
    function getPlayPause(ytplayer){
        if (ytplayer.getPlayerState() ==0){
            return "■";
        } else if (ytplayer.getPlayerState() == 1) {
            return "▶";
        } else if (ytplayer.getPlayerState() == -1) {
            return "";
        } else {
            return "❚❚";
        }
    }
})();