if is ajax,javascript - Check if function is jQuery ajax request - Stack Overflow

The jqXHR objects returned by $.ajax() as of jQuery 1.5 implement the

Promise interface, giving them all the properties, methods, and

behavior of a Promise (see Deferred object for more information).

Available Promise methods of the jqXHR object include:

jqXHR.done(function( data, textStatus, jqXHR ) {}); An alternative

construct to the success callback option, the .done() method replaces

the deprecated jqXHR.success() method. Refer to deferred.done() for

implementation details.

jqXHR.fail(function( jqXHR, textStatus, errorThrown ) {}); An

alternative construct to the error callback option, the .fail() method

replaces the deprecated .error() method. Refer to deferred.fail() for

implementation details.

jqXHR.always(function( data|jqXHR, textStatus, jqXHR|errorThrown ) {

});* An alternative construct to the complete callback option, the

.always() method replaces the deprecated .complete() method.