Pro: You aren't subject to the same-origin policy that XHR has. Con: You can't manipulate the Request (GET only, can't touch headers), and you can't even see t

Pro: You aren't subject to the same-origin policy that XHR has. Con: You can't manipulate the Request (GET only, can't touch headers), and you can't even see the Response -- when you vote on HN it just increments the number it already had instead of getting the new number in the response from the server.