Ajax is a technology that allows web developers to create interactive web applications using a combination of HTML, CSS, and JavaScript. Ajax allows you to make requests to the server without having to reload the page, which makes for a more fluid user experience. Ajax can be used for a variety of tasks, such as
Joomla 3.x has a new component called com_ajax. Which is a thin, extensible component used as a starting point for HTTP requests from modules and plugins.