Table copier (to clipboard) - userscript for Tampermonkey (hopefully other managers too).

table-copier-clipboard.user.js

// ==UserScript==
// @name         Table copier (to clipboard)
// @version      0.3.1
// @description  Choose from your userscipts addon menu. All tables are highlighted, click one to copy, elsewhere to cancel. Copy table and paste into spreadsheets like Excel, Google Sheets, LibreOffice Calc, OpenOffice Calc and others.
// @author       Jakub Marcinkowski <kuba.marcinkowski on g mail>
// @copyright    2024+, Jakub Marcinkowski <kuba.marcinkowski on g mail>
// @license      Zlib
// @namespace    Jakub Marcinkowski
// @homepageURL  https://gist.github.com/JakubMarcinkowski
// @homepageURL  https://github.com/JakubMarcinkowski
// @updateURL    https://gist.github.com/JakubMarcinkowski/dbc55176baa98f1c636817c08ef1c493/raw/table-copier-clipboard.user.meta.js
// @downloadURL  https://gist.github.com/JakubMarcinkowski/dbc55176baa98f1c636817c08ef1c493/raw/table-copier-clipboard.user.js
// @icon         data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHZpZXdCb3g9IjAgMCAxNiAxNiIgY2xpcC1wYXRoPSJjaXJjbGUoKSI+PHJlY3QgZmlsbD0iIzZkOSIgd2lkdGg9IjE2IiBoZWlnaHQ9IjE2Ii8+PHBhdGggZD0iTTIsMFYxNk02LDBWMTZNMTQsMFYxNk0wLDNIMTZNMCw4SDE2TTAsMTNIMTYiIHN0cm9rZT0iIzQ0NSIvPjwvc3ZnPg
// @match        *://*/*
// @noframes
// @run-at       document-idle
// @grant        GM.registerMenuCommand
// @grant        GM.setClipboard
// ==/UserScript==

(function() {
  'use strict';

  if (!('setClipboard' in GM)) return;

  let cleaned = 1;
  let tables = [];
  let tablesBorders = new Map();

  function run() {
    tables = [...document.getElementsByTagName('table')];
    if (tables.length === 1) {
      copyTable(tables[0]);
      tables[0].scrollIntoView({behavior: "smooth", block: "nearest", inline: "nearest"});
      borderHighlight(tables[0]);
      setTimeout(borderNormal, 1000, tables[0]);
    } else {
      tables.forEach(elem => {
        borderHighlight(elem);
        elem.addEventListener('click', takeElem, {capture: true});
        elem.addEventListener('contextmenu', takeElem, {capture: true});
      });
      document.addEventListener('click', stopAll);
    }
  }

  function end() {
    tables.forEach(elem => {
      borderNormal(elem);
      elem.removeEventListener('click', takeElem, {capture: true});
      elem.removeEventListener('contextmenu', takeElem, {capture: true});
    });
    document.removeEventListener('click', stopAll);
    tables = [];
    tablesBorders = new Map();
  }

  function stopAll(e) {
    e.preventDefault();
    e.stopPropagation();
    end();
  }

  function takeElem(e) {
    stopAll(e);
    const table = e.target.tagName === 'TABLE' ? e.target : e.target.closest('table');
    if (table) copyTable(table);
  }

  function borderHighlight(elem) {
    tablesBorders.set(elem, elem.style.border);
    elem.style.border = '2px dashed green';
  }

  function borderNormal(elem) {
    elem.style.border = tablesBorders.get(elem);
  }

  function processTable(table) {
    // When pasting tags from these long selectors (except style), Excel makes additional rows.
    let clone = table.cloneNode(true);
    clone.querySelectorAll('br, wbr, hr, img, style')
    .forEach(elem => {
      elem.remove();
    });
    if (cleaned >= 2) {
      clone.querySelectorAll('a')
      .forEach(link => {
        const span = document.createElement('span');
        span.textContent = link.href;
        link.replaceWith(span);
        span.after(' '); // Separate texts (hrefs)
      });
    }
    if (cleaned === 3) {
      clone.querySelectorAll('*')
      .forEach(elem => {
        if (['SPAN', 'TBODY', 'THEAD', 'TFOOT', 'TR', 'TH', 'TD', 'CAPTION', 'COLGROUP', 'COL'].includes(elem.tagName)) return;
        const span = document.createElement('span');
        for (let child of elem.childNodes) {
          span.append(child);
        }
        elem.replaceWith(span);
      });
    } else {
      clone.querySelectorAll('p, div, h1, h2, h3, h4, h5, h6, ul, li, ol, dl, dt, dd')
      .forEach(elem => {
        const span = document.createElement('span');
        for (let child of elem.childNodes) {
          span.append(child);
        }
        for (let attr of elem.getAttributeNames()) {
          span.setAttribute(attr, elem.getAttribute(attr));
        }
        elem.replaceWith(span);
      });
    }
    return clone;
  }

  function copyTable(table) {
    if (cleaned !== 0) table = processTable(table);
    let param;
    switch (GM.info.scriptHandler) {
      case 'Tampermonkey':
        param = 'html'
        break;
      case 'Violentmonkey':
      case 'Userscripts':
        param = 'text/html'
        break;
      case 'Greasemonkey':
      default:
        param = null;
    }
    if (param) GM.setClipboard(table.outerHTML, param);
    else GM.setClipboard(table.outerHTML);
    // alert(`Table in clipboard. Now paste it into a spreadsheet.`);
  }

  GM.registerMenuCommand('Copy table (full HTML)', () => {cleaned = 0; run();});
  GM.registerMenuCommand('Copy table (cleaned HTML)', () => {cleaned = 1; run();});
  GM.registerMenuCommand('Copy table (cleaned, links as hrefs)', () => {cleaned = 2; run();});
  GM.registerMenuCommand('Copy table (cleanest, links as hrefs)', () => {cleaned = 3; run();});
})();

table-copier-clipboard.user.meta.js

// ==UserScript==
// @name         Table copier (to clipboard)
// @version      0.3.1
// @namespace    Jakub Marcinkowski
// @downloadURL  https://gist.github.com/JakubMarcinkowski/dbc55176baa98f1c636817c08ef1c493/raw/table-copier-clipboard.user.js
// ==/UserScript==

zzz.md

Choose from your userscipts addon menu. All tables are highlighted, click one to copy, elsewhere to cancel. Copy table and paste into spreadsheets like Excel, Google Sheets, LibreOffice Calc, OpenOffice Calc and others.

*.user.js - the bigger file - click RAW to install
*.meta.js - file for updates checks - ignore

After install, new options in UserScript manager appears:

1. Copy table (full HTML)
   Copy full HTML as is. Done, go home.
2. Copy table (cleaned HTML)
   Before copy, cleans tags that, when pasted into Excel, are making additional rows. Bad, don't want.
3. Copy table (cleaned, links as hrefs)
   Clean and additionally replace links with they addresses. Ditch the stupid descriptions.
4. Copy table (cleanest, links as hrefs)
   Replace everything with spans, excepts table building tags and... spans. I am a spanning master.

When an option is activated, with one table on the page, your table is scrolled to and highlighted for a second (so you cen see) and copied to clipboard. With more tables, all are highlighted, now click on the chosen one to copy or on anything else to cancel (culturally).

Example:
https://en.wikipedia.org/wiki/Tampermonkey
On top is a screenshot of a little table from the Wiki. Below, tables copied by options in above order. Notice one row is merged from 3 in the first table.