jQueryUbiquity.js

CmdUtils.CreateCommand({
  name: "jquery",
  preview: "Injects the latest version of jQuery into the current page.",
  execute: function() {
    var s=Application.activeWindow.activeTab.document.createElement('script');
    s.setAttribute('src','http://jquery.com/src/jquery-latest.js');
    Application.activeWindow.activeTab.document.getElementsByTagName('body')[0].appendChild(s);
    displayMessage( "jQuery injected in current page");
  }
});