1. Create a new tab.
  2. Navigate that tab to about:blank.
  3. Paste the following into the location bar: 
    javascript:x = new XMLHttpRequest(); x.open('get', 'http://jquery.com', false); x.send(); alert(x.responseText)
  4. Press "Enter".
  5. If you see the contents of jquery.com appear in an alert dialog, something has gone wrong.