Show the path of a file, before uploading it to a server

I have this code which assigns my file name to upload to my server, this is to register it.

string rutaPDF = Request.MapPath("PDFs_Landing/");
 Random ra = new Random();
 int numeroP = r.Next(5, 10000000);
 tituloLanzamiento = tituloLanzamiento.Replace(" ", "_");
 if (Directory.Exists(rutaPDF) == false)
     Directory.CreateDirectory(rutaPDF);
 string documento = Path.GetFileName(urlPdf.FileName);
 string extensionP = Path.GetExtension(documento);
 documento = documento.Substring(documento.LastIndexOf(".") + 1).ToLower();
 documento = "Documento_" + numeroP + '_' + Pais + extensionP;
 urlPdf.SaveAs(rutaPDF + documento);
 string urlPDF = "/Landing_Page/PDFs_Landing/" + archivo;
 nombreBanner = nombreBanner.Replace("_", " ");

What I want is that before registering, show me the destination route to be able to copy it. I saw an example which implements it like this:

<div class="col-md-6 col-md-offset-5">
    <div class="row">
    <div class="col-md-4">
    <div class="custom-input-file required">
    <input type="file" name="urlPdf" id="urlPdf" class="input-file" onchange="ValidarDocumento(this);" required />
    <label id="errorDoc"></label>
    PDF&nbsp;&nbsp;&nbsp;<i class="fa fa-file text-info"></i>
    <div class="archivo">Click para elegir...</div>
    </div>
    </div>
    </div>
    <a data-toggle="modal" data-target="#myModal">Mostrar Url de Destino</a>
</div>

And this

<div class="modal fade" id="myModal">
    <div class="modal-dialog">
        <div class="modal-content">
            <div class="modal-header">
                <p>
                    Ruta de la imagen del párrafo desde el que se ha hecho click en el modal:
                </p>
            </div>
        </div>
    </div>
</div>


<script>
  $('a[data-toggle=modal]').click(function(){
    var urlPdf = $(this).prev('input').attr('file');

    $($(this).data('target')+' .modal-header p').html(urlPdf);
  });
</script>

But it does not work for me