the "content-part" is currently 25 lines (including the form, url-definitions, etc.) and should be reduced to 10 or so. i am not sure, whether the .js libraries your are mentioning will help with that.
the bigger question is, how many XMLHttpRequests for one browser we want to have more or less in parallel, how to address the multiple instances of one app in browser windows/tabs (names of dom elements), how to bundle/multiplex multiple inquirers in a single HTTPrequests and answer sets. In other words, would not be optimal, if for every ajax application instance, separate XMLHttpRequests whould be created, all of these polling the server for updates. one poll should provide data for all inquirers. registering callbacks in js look like a good idea...
The situation might be different in your situation, i would assume, that once the "cinematic effects" are done (whatever these are) no more requests are needed.