You have 2 options, use $.ajax() or $.ajaxSetup().
Using $.ajax():
$.ajax({
type: 'POST',
url: url,
data: data,
success: success
dataType: dataType
});
Or, before your post run $.ajaxSetup(), but this affects all ajax requests:
$.ajaxSetup({
beforeSend: myFunc,
complete: myCompleteFunc
});