How Rails implements Ajax

When the browser displays the initial web page, different user actions cause it to display a new web page or prompt an Ajax operation:

1.A trigger action occurs and this could be because of the user clicking on a link or button or the user making changes to the information on a form in a field or just an interrupted activation.
2.Data linked with the trigger is sent to an action handler on the server through XMLHttpRequest.
3.The server-side action handler takes some action basing on the data and returns with a response, an HTML fragment.
4.The client-side Javascript accepts the HTML fragment and uses it to update a particular portion of the current page’s HTML, often the content of a