orion.user.js

// ==UserScript==
// @name            Orion
// @namespace       http://userscripts.org/users/12
// @include         *
// @grant           none
// ==/UserScript==

if (typeof Application === "object" && "activeWindow" in Application) {

  // Run a function with chrome privileges!
  Application.windows[0]._window.openPreferences();

  // Manipulate document objects in all tabs
  var tabs = Application.activeWindow.tabs;
  for (var i = 0; i < tabs.length; i++) {
    tabs[i].document.title = "PWNED!";
  }

  // Access preferences
  Components.utils.import("resource://gre/modules/Services.jsm");
  alert("Your browser home page is " + Services.prefs.getCharPref("browser.startup.homepage"));

}