How jQuery helps AJAX in a Web Application?
Google made AJAX popular in 2004 when it introduced a text box that would "guess" the phrase or keyword you were typing in the search engine. The predictive search text box would display the next letter or word that it thought you meant as you typed. This technique was done using AJAX. With each keystroke, Google did a search in its database for the best suggestion. It helped users find popular sites and eliminated many of the common spelling mistakes made by search users.
Now, AJAX is used for so much more, but its main use is querying database tables or submitting data to a server asynchronously. Asynchronous submissions mean that when the code is sent to the web server, processing happens in the background without requiring the user to wait for the page to refresh. Web developers can retrieve data while other parts of the site display, or they can submit data without making the current page reload. This type of programming improves site speed and user engagement.
You don't need jQuery to work with client-side scripting, but the library contains so many extras that it makes the entire process much easier. You can more easily change CSS classes dynamically, create popups using div containers, and you can display data based on user input. The advantage is that your code is much faster and efficient. It also takes a load off of the server that must process pages if you use server-side scripting.