4chan WebM Auto-Resume

Resumes playback of paused WebM videos when scrolled into view

Truy cập trang web của tác giả để được hỗ trợ, đặt câu hỏi, đăng đánh giá hoặc báo cáo tập lệnh.

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// ==UserScript==
// @name         4chan WebM Auto-Resume
// @description  Resumes playback of paused WebM videos when scrolled into view
// @namespace    https://github.com/marktaiwan/
// @homepageURL  https://github.com/marktaiwan/4chan-Webm-Auto-Resume
// @supportURL   https://github.com/marktaiwan/4chan-Webm-Auto-Resume/issues
// @license      MIT
// @version      0.3
// @author       Marker
// @include      *//boards.4chan.org/*
// @include      *//boards.4channel.org/*
// @grant        none
// @noframe
// ==/UserScript==

(function () {
'use strict';
const interval = 100; // millisecond
let lastExecution = Date.now();

function isVisible(ele) {
  const {top, bottom} = ele.getBoundingClientRect();
  return (top > 0 || bottom > 0) && (top < document.documentElement.clientHeight);
}

function pausedByUser(video) {
  return (video.dataset.userPauseState === '1');
}

function pauseHandler(event) {
  const video = event.target;

  // Video is still in view when paused, therefore it's triggered by the user
  if (isVisible(video)) video.dataset.userPauseState = '1';
}

function playHandler(event) {
  const video = event.target;
  if (pausedByUser(video)) video.dataset.userPauseState = '0';
}

function initVideoElement(video) {
  if (video.dataset.userPauseState === undefined) {
    video.dataset.userPauseState = '0';
    video.addEventListener('pause', pauseHandler);
    video.addEventListener('play', playHandler);
  }
}

document.addEventListener('scroll', () => {
  if (Date.now() - lastExecution > interval) {
    window.setTimeout(function () {
      const expandedVideos = document.querySelectorAll('.expandedWebm');
      for (const video of expandedVideos) {
        initVideoElement(video);
        if (video.paused && isVisible(video) && !pausedByUser(video)) {
          video.play().catch(() => {/* noop */});
        }
      }
    }, interval);
    lastExecution = Date.now();
  }
});
})();