Gerrit/jira keybinding ignore tampermonkey script

gistfile1.txt

// ==UserScript==
// @name         Gerrit/jira keybinding ignore
// @namespace    http://tampermonkey.net/
// @version      0.2
// @description  Stop gerrit/jira from adding bindings to up-/down-arrow keys.
// @author       http://github.com/kormat
// @match        https://gerrit.wikimedia.org/*
// @match        https://jira.mariadb.org/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    var keycodes = [38, 40]; // Up-arrow and Down-arrow

    document.addEventListener('keydown', function(e) {
        if (keycodes.indexOf(e.keyCode) != -1)
        {
            e.cancelBubble = true;
            e.stopImmediatePropagation();
        }
        return false;
    }, true);

})();