Call to jquery ajax - .fail vs. :error

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
}
});
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最佳答案

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(...);
});
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Just to freshen this up...

The success and error approach have been deprecated as of jQuery 1.8.

jQuery Ajax

Deprecation Notice: The jqXHR.success(), jqXHR.error(), and jqXHR.complete() callbacks are deprecated as of jQuery 1.8. To prepare your code for their eventual removal, use jqXHR.done(), jqXHR.fail(), and jqXHR.always() instead.

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Using the chainable deferred object promise style allows for a cleaner structure and the use of always.

let data = {"key":"value"}


$.ajax({
type: 'PUT',
url: 'http://example.com/api',
contentType: 'application/json',
data: JSON.stringify(data),
}).done(function () {
console.log('SUCCESS');
}).fail(function (msg) {
console.log('FAIL');
}).always(function (msg) {
console.log('ALWAYS');
});

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