Javascript issue? & Nginx upload progress code wor

Question

I am trying to show progress upload information on the same page as I start upload (for example index.php). So I simply start upload, it uploads, I open new tab http://domain.com/progress?X-Progress-ID=test and see the JSON output: { "state" : "uploading", "received" : 4422060, "size" : 5358641366 }

But Jquery script does not want to work.. However if I let file being uploaded and open this page in next tab, javascript shows me needed information. How to fit this into one file to make it work? So I start uploading a file and then it starts to show me response from calling GET another url.

Thanks in advance.

Form

<form id="upload" action="/upload/?X-Progress-ID=test" enctype="multipart/form-data" method="post">
  <label for="jfile">File Upload:
    <input id="jfile" name="file" type="file" />
  </label>
  <input type="submit" value="Upload File" />
</form>

Jquery

   <script>
    $(function() {
        setInterval(function() {
            $.ajax({
            type: 'GET',
                url: '/progress?X-Progress-ID=test',
                dataType: 'json',
                cache: false,
                success: function (data) {
                       alert(data.state);
               });
        }, 500);
    });
    </script>