How do I get the HTTP status code with jQuery?

I want to check if a page returns the status code 401. Is this possible?

Here is my try, but it only returns 0.

$.ajax({
    url: "http://my-ip/test/test.php",
    data: {},
    complete: function(xhr, statusText){
    alert(xhr.status); 
    }
});

this is possible with jQuery $.ajax() method

$.ajax(serverUrl, {
   type: OutageViewModel.Id() == 0 ? "POST" : "PUT",
   data: dataToSave,
   statusCode: {
      200: function (response) {
         alert('1');
         AfterSavedAll();
      },
      201: function (response) {
         alert('1');
         AfterSavedAll();
      },
      400: function (response) {
         alert('1');
         bootbox.alert('<span style="color:Red;">Error While Saving Outage Entry Please Check</span>', function () { });
      },
      404: function (response) {
         alert('1');
         bootbox.alert('<span style="color:Red;">Error While Saving Outage Entry Please Check</span>', function () { });
      }
   }, success: function () {
      alert('1');
   },
});

The third argument is the XMLHttpRequest object, so you can do whatever you want.

$.ajax({
  url  : 'http://example.com',
  type : 'post',
  data : 'a=b'
}).done(function(data, statusText, xhr){
  var status = xhr.status;                //200
  var head = xhr.getAllResponseHeaders(); //Detail header info
});

Use the error callback.

For example:

jQuery.ajax({'url': '/this_is_not_found', data: {}, error: function(xhr, status) {
    alert(xhr.status); }
});

Will alert 404

I think you should also implement the error function of the $.ajax method.

error(XMLHttpRequest, textStatus, errorThrown)Function

A function to be called if the request fails. The function is passed three arguments: The XMLHttpRequest object, a string describing the type of error that occurred and an optional exception object, if one occurred. Possible values for the second argument (besides null) are "timeout", "error", "notmodified" and "parsererror".

$.ajax({
    url: "http://my-ip/test/test.php",
    data: {},
    complete: function(xhr, statusText){
        alert(xhr.status); 
    },
    error: function(xhr, statusText, err){
        alert("Error:" + xhr.status); 
    }
});