jQuery has a number of built-in AJAX functions and $.ajax() or jQuery.ajax() is one of them.
Most of the time, we'll use one or two of them, but there is one method that rules them all. It's the generic version of the call and it's simply called $.ajax().
$.ajax() is quite powerful ajax function because it enables us to pass parameters too to the PHP file to get the filtered result.
Copy the following code and paste in your .html file.
<button id="homeBtn">HOME</button> <button id="aboutBtn">ABOUT US</button> <button id="coursesBtn">COURSES</button> <span id='loadc'></span>