'Pause' and 'Return' AJAX

Question

I have a code on my page that uploads files.

These files that are sent, have specific fields filled (Ex: name, phone, email) and it is not possible to change this type of document. If one leaves a field blank, it will be blank. However I need this information.

The upload is sent by jQuery to another PHP page where the whole process of reading this document and saving in the database is done and returns a message (sucess/ error).

My question is, is there any way to, upon noticing the blank field in the document return the message, open a popup, and fill in an input, and resume AJAX from where it left off with the new information?

---

Thank you, I use the following code for HTML view:

<form id="upload" method="post" action="upload.php" enctype="multipart/form-data">
   <div id="drop">
      Arraste os arquivos ZIP aqui
      <br/>
      <a>Pesquisar...</a>
      <input type="file" name="upl" multiple />
   </div>
   <ul>
      <!-- The file uploads will be shown here -->
   </ul>
</form>

<!-- JavaScript Includes -->
<script src="assets/js/jquery.knob.js"></script>

<!-- jQuery File Upload Dependencies -->
<script src="assets/js/jquery.ui.widget.js"></script>
<script src="assets/js/jquery.iframe-transport.js"></script>
<script src="assets/js/jquery.fileupload.js"></script>

<!-- Our main JS file -->
<script src="assets/js/script.js"></script>

Together with the library of jQuery File Upload

---

'upload.php' to where the FORM is sent without page reload:

$allowed = array('zip');

if(isset($_FILES['upl']) && $_FILES['upl']['error'] == 0){

    $filename = $_FILES['upl']['name'];
    $source = $_FILES['upl']['tmp_name'];
    $type = $_FILES['upl']['type'];

    $name = explode('.', $filename);
    $target = 'uploads/extracted/' . $name[0] . '-' . time() . '/';
    $target2 = 'uploads/extracted/' . $name[0] . '-' . time();

    $extension = pathinfo($_FILES['upl']['name'], PATHINFO_EXTENSION);

    if(!in_array(strtolower($extension), $allowed)){
        echo '{"status":"error"}';
        exit;
    }

    if(move_uploaded_file($source, 'uploads/'.$filename)){
        // INICIA CÓDIGO PARA SALVAR INFO NO DB
        // Solicita NANODicom
        require 'nanodicom/nanodicom.php';

        // Cria pasta caso não exista
        if(!is_dir($target)){
            mkdir($target, 0744);
        }

        $zip = new ZipArchive();
        $x = $zip->open('uploads/'.$filename);

        // Extrai arquivos
        if($x === true) {
            $zip->extractTo($target);
            $zip->close();
        } else {
            echo '{"status":"error"}';
            exit;
        }

        // Procura por arquivos DCM nas pastas      
        $ar = array();
        $studyID = array();
        $files = findDcm($target2);

        // INICIO da leitura dos DCM com NANODicom
        if($files === true){
            foreach ($ar as $file){
                try{
                    // 2) Load only given tags. It will stop once all given tags are found. Fastest!
                    $dicom = Nanodicom::factory($file, 'simple');
                    // Only a small subset of the dictionary entries were loaded
                    $dicom->parse()->profiler_diff('parse')."<br/>";

                    // Verifica se existe exames diferentes
                    if(!in_array($dicom->value(0x0020, 0x0010), $studyID) || !count($studyID)){
                        $studyID[] = $dicom->value(0x0020, 0x0010);

                        $exame = saveStudy($dicom, "uploads/$filename");

                        if(!$exame){
                            echo '{"status":"error"}';
                            exit;
                        }
                    }

                    unset($dicom);
                } catch (Nanodicom_Exception $e){
                    echo '{"status":"error"}';
                    exit;
                }
            }
        } else{
            echo '{"status":"error"}';
            exit;
        }
        // FIM da leitura dos DCM

        // Exclui pasta para ganhar espaço
        $result = delTree($target2);
        // FIM CÓDIGO PARA SALVAR INFO NO DB
        echo '{"status":"success"}';
        exit;
    } else{
        echo 'erro ao gravar arquivo.';
        echo '{"status":"error"}';
        exit;
    }
}

//echo 'erro arquivo: '.$_FILES['upl']['error'];
echo '{"status":"error"}';
exit;

The function findDcm() searches folder by folder by files with . dcm which is the file type that is sent.

The saveStudy() function saves variables in the database.

Checking whether the value exists inside the file can be done both here and in saveStudy(), but once you check that a value is empty you need to return some message with an input field for the user to fill in the missing value.