Since it is asynch and there may be several in parallel I would prefer a solution which supports multiple parallel requests and knows which success/fail belongs to which request – probably using The jqXHR Object as described at http://api.jquery.com/jQuery.post/ (?).
Since I am just learning, a complete code example which I can study and understand would be most welcome.
HTML5’s Web Workers will allow you to have a multi threaded solution in JS. If you’re willing to experiment with them, they’re supported in Opera, Chrome and Firefox (haven’t tested it on IE yet). Check them out.