Ajax Request Response
AJAX (Asynchronous Javascript and XML)   This is a client side script that use to get and pass data from and to the server or database without completely refreshing or without any post back. Mainly use to update a web page partially.   simple ajax request/response   $. ajax ({   type :'GET' ,  //this specifies the type of the request. ex:- GET , POST   url :'getDataFromThisURL.php' ,  //this specifies the url which should be redirect when the ajax                                                                 //response executes   data :{key:value} ,  //this is optional. if we have to pass any data(ex:-form data) then we should pass                                  //that data like this. in here KEY  is the variable which will pass with the requ...