ajax_status_code.js

$.ajax({
  method: "POST",
  url: "database.php",
  data: {
    user: $("input[name=username").val(),
    pass: $("input[name=password").val()
  },
  statusCode: {
    500: function() {
      response.html('Error : 500');
    }
  }
}).done(function(data){
  if(data == 1)
    response.html('Login berhasil !');
  else if(data == 2)
    response.html('Login gagal.');
});