Call to jquery ajax - .fail vs. :error

Question

Which one should I use?

Is there any reason to use one rather than the other?

Is one better for error handling?

$.ajax({     url: url,     data: { start: start, end: end } }).done(function(data, textStatus, jqXHR) {     $('#myElement').append(data); }).fail(function() {     // report error     }); 

OR

$.ajax({     url: url,     data: { start: start, end: end },     success: function(data, textStatus, jqXHR) {         $('#myElement').append(data);     },     error: function(jqXHR, textStatus, errorThrown) {         // report error     } }); 

Answer 1

The two options are equivalent.

However, the promise-style interface (.fail() and .done()) allow you to separate the code creating the request from the code handling the response.

You can write a function that sends an AJAX request and returns the jqXHR object, and then call that function elsewhere and add a handler.

When combined with the .pipe() function, the promise-style interface can also help reduce nesting when making multiple AJAX calls:

$.ajax(...)     .pipe(function() {          return $.ajax(...);     })     .pipe(function() {          return $.ajax(...);     })     .pipe(function() {          return $.ajax(...);     });