How to Use Apex:actionSupport tag in Visualforce Page.
<apex:actionSupport>
A
component that adds AJAX support to another component, allowing the
component to be refreshed asynchronously by the server when a particular
event occurs, such as a button click or mouseover.
actionSupport component adds AJAX support to other components in visualforce. It allows components to be refreshed asynchronously by calling the controller’s method when any event occurs (like click on button). It allows us to do partial page refresh asynchronously without refreshing full page.
In the example below, initially count value is set...
