通话时$。的进度

I am trying to do some AJAX call using $.when and $.then functions. I am using these functions to fill a template and so , in the meanwhile , I want to fill the form that I will fill with some message like

"loading data.. please wait"

I found out that there is a progress functions but it works only with notify. I searched through the community and I noticed that it is used with the promise call. I did not really get the meaning of promise and how deferred objects are working in my script.

This is my script :

         $.when(e.get_info('get_utente'))
            }).then(function(data){
                 $('#username').val(data.username);
                 $('#email').val(data.email);
         })

I would like to insert progress beetween this two calls. Sorry if there's some misunderstanding , but 'till now I was using ASYNC : false , and after i noticed that is a really bad idea I found out deferred objects , but i dindn't get at all it's logic

The progress callback doesn't really apply to ajax requests at this time.

Instead, do your "loading data.. please wait" message before $.when.

Also, you don't need $.when at all, just do

$("#loading").show();
e.get_info('get_utente').done(function(data){
    $("#loading").hide();
    $('#username').val(data.username);
    $('#email').val(data.email);
});

$.when is only needed if you need to run something when 2 or more promise objects are complete. For a single promise object, it is not needed.