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Get YouTube Thumbnail

Adds button to view largest thumbnail image for any video

当前为 2018-03-07 提交的版本，查看 最新版本。

  1. // ==UserScript==
  2. // @name            Get YouTube Thumbnail
  3. // @version         0.4
  4. // @description     Adds button to view largest thumbnail image for any video
  5. // @author          Drazen Bjelovuk
  6. // @match           *://www.youtube.com/*
  7. // @grant           none
  8. // @run-at          document-end
  9. // @namespace       https://greasyfork.org/users/11679
  10. // @contributionURL https://goo.gl/dYIygm
  11. // ==/UserScript==
  12.  
  13. document.addEventListener('spfdone', addThumbnailButton);
  14. document.addEventListener('yt-navigate-start', addThumbnailButton);
  15.  
  16. addThumbnailButton();
  17.  
  18. const sizes = ['/maxresdefault.jpg', '/hqdefault.jpg', '/mqdefault.jpg', '/sddefault.jpg'];
  19. var vidId;
  20.  
  21. function tryLoad(index) {
  22.     var image = new Image();
  23.     image.onload = function(img) {
  24.         if (img.path[0].naturalWidth > 120) {
  25.             window.open(img.path[0].src);
  26.         }
  27.         else if (index < sizes.length - 1) {
  28.             tryLoad(index + 1);
  29.         }
  30.     };
  31.     image.src = 'https://img.youtube.com/vi/'+ vidId + sizes[index];
  32. }
  33.  
  34. function addThumbnailButton() {
  35.     var button = document.getElementById('viewThumbnailBtn');
  36.     if (button) button.remove();
  37.  
  38.     var subscribeButton = document.querySelector('#subscribe-button');
  39.     if (subscribeButton) {
  40.         button = document.createElement('paper-button');
  41.         button.id = 'viewThumbnailBtn';
  42.         button.className = 'style-scope ytd-subscribe-button-renderer';
  43.         button.style.cssText = 'margin-left: auto';
  44.         button.textContent = 'View Thumbnail';
  45.         button.onclick = function() {
  46.             vidId = document.querySelector('ytd-watch').getAttribute('video-id');
  47.             tryLoad(0);
  48.         };
  49.         subscribeButton.parentNode.insertBefore(button, subscribeButton);
  50.     }
  51.     else if (window.location.href.indexOf('v=') > -1) {
  52.         setTimeout(addThumbnailButton, 500);
  53.     }
  54. }