Quick Coding help needed javascript

I have using a google extension based on [login to view URL] (please install it from google chrome store to put description in context) starting on line 74 of [login to view URL] in the code the javascript is doing a post to an asp page. (line 119) I am trying to find out what the response is that the page is sending back to confirm the upload (as i do not have access to [login to view URL] source. Basically what i want to do is change the destination page but i want to do the relevant response back that the code is waiting for to confirm the upload is complete or failed.