Problem with return value from JQuery call

Problem with return value from JQuery call

I have a JQuery script which calls a PHP file (should it be a PHP function instead?)   The script only shows the "not working"-alert box, and alert(output) displays nothing.

The PHP file can return only 2 values, ('1' or '0')

This is my JQuery code:
<script src=" http://code.jquery.com/jquery-1.11.1.min.js"></script>
<script>
       function checkCountry(country)
       {
            $.ajax(
            {
                url: 'ajax/getCountryState.php',
             data: {country: '1'},
             type: 'POST',
             success: function(output) {
             if (output == 1) alert('success');
             else alert('not working');
                 alert(output);
      }

            });
            }

</script>   

the PHP function just returns the '1' or '0' value, I mean it doesn't do any converting to JSON or anything like that

The goal is when user has made a selection in a select list I should update the form based on what the user selected.