Error in jQuery code, can you help?

Question

JavaScript

Toasters, hello)
In general, I have a site written in oop.
There is a button "Output" and when pressed, it should write to the database and display a window with a message.
All windows and everything is there, but when you click an error:


The code itself:

$(document).ready(function() {
  $('form').submit(function(event) {
    if ($(this).attr('id') == 'no_ajax') {
      return;
    }
    var json;
    event.preventDefault();
    $.ajax({
      type: $(this).attr('method'),
      url: $(this).attr('action'),
      data: new FormData(this),
      contentType: false,
      cache: false,
      processData: false,
      success: function(result) {
        json = jQuery.parseJSON(result);
        if (json.url) {
          window.location.href = '/' + json.url;
        } else {
          alert(json.status + ' - ' + json.message);
        }
      },
    });
  });
});

Without this file, everything works, the database is recorded but the window does not pop up and it just redirects to the page with the answer (a bit complicated scheme)

Please help me, why is this so?

Answer 1

result is apparently empty