Specify dataType: "html"
.
If you do not jQuery will guess the requested data type (check: http://api.jquery.com/jQuery.ajax/). My guess is that in your case response
was a String
rather than a DOMObject
. Obviously DOM methods won't work on a String.
You could test that with console.log("type of response: " + typeof response)
(or alert("type of response:" + typeof response)
, in case you don't run Firebug)