Ajax can make visible changes without having to reload page and don't interrupt user, providing faster working functionalities.
Multiple independent operations can be performed using the technique called XMLHttpRequest.
The main goal is to make web pages that can update the page faster with a small amount of data exchange with the server in the background, thus saving the user the trouble of updating the entire web page at any time. This means increasing the interaction, speed and usability of the web page.
Basic Ajax Code Structure and Usage