404 not found!

I am getting  a 404 error from this GET 

background.js:27 GET http://localhost/subit_backend.php 404 (Not Found)
background.js:27 XHR failed loading: GET "http://localhost/subit_backend.php".

            var xhr = new XMLHttpRequest();
            xhr.onerror = function() { alert('error'); };
            xhr.open("GET", "http://localhost/subit_backend.php", true);
            xhr.send(jsonResponse["email"]);

my Document Root in httpd.conf is:

DocumentRoot "C:/xampp/htdocs/sub_crud"

<Directory "C:/xampp/htdocs/sub_crud">

subit_backend.php is in my controllers directory. 

where is my path going wrong?

proof that an old dog can learn new tricks