remove-disable-copy.user.js

// ==UserScript==
// @name         Remove disable copy
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       You
// @match        *://*/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';
    var head = document.getElementsByTagName('head')[0];
    var style = document.createElement('style');
    var cssText = document.createTextNode('*{-webkit-user-select:text!important;-moz-user-select:text!important;-ms-user-select:text!important;user-select:text!important}');
    style.appendChild(cssText);
    head.appendChild(style);
    // Your code here...
})();