Youtube 書き起こしベースの早送り.user.js

Youtube:floating transcript.user.js

// ==UserScript==
// @name        Youtube:floating transcript 
// @namespace   http://efcl.info/
// @description apply panel floating
// @include     https://www.youtube.com/watch?v=*
// @version     1
// @grant       none
// ==/UserScript==
// Usage: Open Transcript panel
// -> next transcript
// <- prev transcript
function GM_addStyle(aCss) {
  'use strict';
  let head = document.getElementsByTagName('head')[0];
  if (head) {
    let style = document.createElement('style');
    style.setAttribute('type', 'text/css');
    style.textContent = aCss;
    head.appendChild(style);
    return style;
  }
  return null;
}


GM_addStyle(`
#watch-transcript-container {
    position:fixed;
    top: 100px;
    right:0;
    z-index:123456;
    background-color: white;
    padding: 1rem;
}
#watch-transcript-container{
    max-height: 32em;
}
#watch-transcript-container #transcript-scrollbox{
    max-height: 30em;
}
`);

var _cacheNext, _cachePrev;
function nextTranscript(){
    var currentTranscript = document.querySelector(".caption-line.caption-line-highlight");
    var next = currentTranscript.nextElementSibling;
    if(next === _cacheNext){
        next = next.nextElementSibling;
    }
    _cacheNext=next;
    next.click();
}
function prevTranscript(){
    var currentTranscript = document.querySelector(".caption-line.caption-line-highlight");
    var prev = currentTranscript.prevElementSibiling;
    if(prev === _cachePrev){
        prev = next.prevElementSibiling;
    }
    _cachePrev = prev;
    prev.click();

}
function onKeyCode(event, keyCode) {
    switch (keyCode) {
        case 38:// UP
            event.preventDefault();
            prevTranscript();
            break;
        case 40:// Down
            event.preventDefault();
            nextTranscript();
            break;
        case 39:// Right
            event.preventDefault();
            nextTranscript();
            break;
        case 37:// Left
            event.preventDefault();
            prevTranscript();
            break;
    }
}
document.addEventListener("keydown", (event) => {
    onKeyCode(event, event.keyCode)
});

Can you make scripts that set a timer to automatically pause/stop on all Youtube embed videos? Like pause a video after X seconds!!?