// ==UserScript==
// @name         YouTube Auto Insert User Name Into Comment Reply Box
// @namespace    YouTubeAutoInsertUserNameIntoCommentReplyBox
// @version      1.0.1
// @description  Automatically insert the user name whom you're replying to into the comment reply's edit box.
// @author       jcunews
// @include      https://www.youtube.com/*
// @grant        none
// ==/UserScript==
addEventListener("click", function(ev, ele, author) {
ele = ev.target;
if (!ele.classList.contains("comment-renderer-reply")) return;
ele = ele.parentNode.parentNode;
author = ele.parentNode.querySelector(".comment-author-text");
if (!author || !(ele = ele.querySelector(".comment-simplebox-text"))) return;
ele.innerHTML = "+" + author.outerHTML + ": ";
});