Block Opener on Targeted Links

Add rel attribute values on mouseup to block window.opener in the linked site, also blocks referer (2016-09-01)

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Userscripts to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install a user script manager extension to install this script.

(I already have a user script manager, let me install it!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name        Block Opener on Targeted Links
// @namespace   JeffersonScher
// @description Add rel attribute values on mouseup to block window.opener in the linked site, also blocks referer (2016-09-01)
// @author      Jefferson "jscher2000" Scher
// @copyright   Copyright 2016 Jefferson Scher
// @license     BSD 3-clause
// @include     *
// @version     0.5
// @grant       none
// ==/UserScript==

// Check what was clicked and rel it up if needed
function BOoTL_relfix(evt){
  // is it always a link? are there other cases?
  var tgt = evt.target;
  if (tgt.nodeName != "A") return;
  // did we already hack it?
  if (tgt.hasAttribute("bootl")) return;
  // is it different origin?
  if (tgt.hostname == location.hostname) return;
  // does it have a target not replacing the page?
  var tgtatt = tgt.getAttribute("target") || "_self";
  if ("_self|_parent|_top".indexOf(tgtatt) > -1) return;
  // OKAY THEN add rel values + mark as modified
  var oldrel = tgt.getAttribute("rel") || "";
  tgt.setAttribute("rel", "noopener noreferrer "+oldrel);
  tgt.setAttribute("bootl", tgt.getAttribute("rel"));
}
// Add click event listener to the body
document.body.addEventListener("mouseup", BOoTL_relfix, false);