Disable YouTube Spacebar Scrolling

DisableYoutubeScrolling.user.js

// ==UserScript==
// @name         Disable YouTube spacebar scrolling
// @namespace    http://tampermonkey.net/
// @version      0.2
// @description  Disables spacebar scrolling and forces it to pause the video instead
// @author       HPZ07
// @match        https://www.youtube.com/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    window.addEventListener('keydown', function(e) {
        if (e.keyCode === 32 && e.target === document.body && isWatchPage()) {
            e.preventDefault();
            var video = document.querySelector('video.html5-main-video');
            if (video.currentTime > 0 && !video.paused && !video.ended) {
                video.play();
            } else {
                video.pause();
            }
        }
    });

    function isWatchPage() {
        return /^\/watch/.test(location.pathname);
    }

})();