Dynamically get Probability based on Stage Name - Visualforce

How to show Probability based on the stage name?

Before knowing about it, a couple of important things needs to known

• 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.
• ActionRegion : An area of a Visualforce page that demarcates which components should be processed by the Force.com server when an AJAX request is generated. Only the components in the body of the <apex:actionRegion> are processed by the server, thereby increasing the performance of the page.

For more details, <apex:actionRegion> , <apex:actionSupport>

So to understand about the Probability field in the Sales process - Probability on Sales Process