Okay, so AJAX can be used when we want to update small portions of a webpage at a time. When would this be useful? Like when posting on a site?

Answer 1

yes, that's and example. Other one is some web pages that uses modal windows to send some info and then update some parts of the web with the asynchronous response. For example: a modal login.

Answer 2

like to submit a search query to the server and getting back the response