No, but that's not the point. If the web page is telling you "Wait, your email is being sent" and you close your browser, do you expect the email to be sent? Or if it says "Please wait, the document is being saved" and you close the application..

I.e. The point is that asynchronous make it feels smoother. If the browser crashes while data is being transmitted, there's nothing you can do. Ajax, asynchronous or whatever. So, what will happens is the data will be lost. The asynchronous part doesn't resolve all problems.. it just feel faster for the user.

And, by the way, why the ":)" at the end? Is it because you were happy? Personally, I find that a bit provocative. (i.e. in gaming, people would say "You suck :)" or if they'd crush you, they would just say :). It's being bad manner.) But then, if you were happy and just wanted to show it, sorry for this comment.