PreventBrowserHijacking.user.js

// ==UserScript==
// @name         Prevent Browser Hijacking
// @description  Hit Ctrl+Shift+F12 to stop sites from breaking standard browser functionality like copy and paste
// @version      1.1.1
// @author       heavyLobster2
// @namespace    github.com/heavyLobster2
// @downloadURL  https://gist.github.com/heavyLobster2/b2545b34941ed891f4d19390bc0a6e7b/raw/PreventBrowserHijacking.user.js
// @match        *://*/*
// @run-at       document-start
// @grant        none
// ==/UserScript==
(function () {
    "use strict";
    
    var all = false;
    
    function toggleAll() {
        all = !all;
    }
    
    function stop(event) {
        event.stopImmediatePropagation();
    }
    
    function stopIfAll(event) {
        if (all) stop(event);
    }
    
    var listeners = new Map([
        ["keydown", function (e) {
            if (e.code === "F12") {  //F12
                if (e.ctrlKey && e.altKey && e.shiftKey) {  //Ctrl+Alt+Shift+F12
                    suicide();
                } else if (e.ctrlKey && e.shiftKey) {  //Ctrl+Shift+F12
                    toggleAll();
                } else if (e.ctrlKey) {  //Ctrl+F12
                    debugger;
                }
                stop(e);
				    } else if (e.ctrlKey && e.shiftKey && e.code === "KeyI") {    //Ctrl+Shift+I
                stop(e);
            }
        }],
        ["click", function (e) {
            if (e.button === 1) {  //middle-click
                stop(e);
            } else {
                stopIfAll(e);
            }
        }],
        ["mousedown", function (e) {
            stopIfAll(e);
        }],
        ["cut", function (e) {
            stopIfAll(e);
        }],
        ["copy", function (e) {
            stopIfAll(e);
        }],
        ["paste", function (e) {
            stopIfAll(e);
        }],
        ["contextmenu", function (e) {
            stopIfAll(e);
        }],
        ["drag", function (e) {
            stopIfAll(e);
        }],
        ["drop", function (e) {
            stopIfAll(e);
        }]
    ]);
    
    listeners.forEach(function (value, key) {
        window.addEventListener(key, value, true);
    });
    
    function suicide() {
        listeners.forEach(function (value, key, map) {
            window.removeEventListener(key, value, true);
        });
    }
})();