Raw Source
tbmale / torrentz2 magnet link creator 

// ==UserScript==
// @name        torrentz2 magnet link creator
// @version     0.1
// @author      tbmale
// @description add a button for copying automagicaly created magnet link to clipboard using trackers listed for this item
// @include     https://torrentz2.eu/*
// @grant       none
// @license     MIT
// ==/UserScript==

if (location.toString().split('/')[3] === undefined) return;
if (location.toString().split('/')[3].indexOf('search') != -1) return;
if (location.toString().split('/')[3].indexOf('my') != -1) return;
if (location.toString().split('/')[3].indexOf('help') != -1) return;

var trackdiv = document.getElementsByClassName('trackers')[0].firstChild;
var downlinks = document.getElementsByClassName('downurls')[0];
var magbutt = document.createElement('button');
var hashtext = trackdiv.lastChild.cloneNode(true);
var maglink = document.createElement('a');
var hash = trackdiv.lastChild.textContent.split('info_hash: ')[1].trim();
var magurl = 'magnet:?xt=urn:btih:' + hash;

magbutt.innerText = 'Copy magnet to clipboard';
magbutt = downlinks.insertBefore(magbutt, downlinks.firstChild.nextSibling.nextSibling);
magbutt.addEventListener('click', copytoclipboard);
maglink = downlinks.insertBefore(maglink, downlinks.lastChild);
maglink.appendChild(hashtext);
trackdiv.lastChild.remove();
//while (trackdiv.nextSibling.nodeName == 'DL' || trackdiv.nextSibling.nodeName == '#text') {
while (trackdiv) {
  if (trackdiv.firstChild && trackdiv.firstChild.nodeName == 'DT') magurl += '&tr=' + encodeURIComponent(trackdiv.firstChild.firstChild.textContent);
  trackdiv = trackdiv.nextSibling;
}
maglink.href = magurl;
console.log(magurl);

function copytoclipboard(ev) {
  // directly from https://stackoverflow.com/a/30810322/1649010

  var textArea = document.createElement("textarea");

  //
  // *** This styling is an extra step which is likely not required. ***
  //
  // Why is it here? To ensure:
  // 1. the element is able to have focus and selection.
  // 2. if element was to flash render it has minimal visual impact.
  // 3. less flakyness with selection and copying which **might** occur if
  //    the textarea element is not visible.
  //
  // The likelihood is the element won't even render, not even a flash,
  // so some of these are just precautions. However in IE the element
  // is visible whilst the popup box asking the user for permission for
  // the web page to copy to the clipboard.
  //

  // Place in top-left corner of screen regardless of scroll position.
  textArea.style.position = 'fixed';
  textArea.style.top = 0;
  textArea.style.left = 0;

  // Ensure it has a small width and height. Setting to 1px / 1em
  // doesn't work as this gives a negative w/h on some browsers.
  textArea.style.width = '2em';
  textArea.style.height = '2em';

  // We don't need padding, reducing the size if it does flash render.
  textArea.style.padding = 0;

  // Clean up any borders.
  textArea.style.border = 'none';
  textArea.style.outline = 'none';
  textArea.style.boxShadow = 'none';

  // Avoid flash of white box if rendered for any reason.
  textArea.style.background = 'transparent';

  textArea.value = maglink;

  document.body.appendChild(textArea);

  textArea.select();

  try {
    var successful = document.execCommand('copy');
    var msg = successful ? 'successful' : 'unsuccessful';
    console.log('Copying text command was ' + msg);
  }
  catch (err) {
    console.log('Oops, unable to copy');
  }

  document.body.removeChild(textArea);
}