var elems = $x('//*[@class="name_class"]'),
      firstElem;
if(elems.length) {
   firstElem = elems[0];
}
console.log(firstElem);

[HttpPost()]
public async Task<HttpResponseMessage> Post()
{
    if (!Request.Content.IsMimeMultipartContent())
    {
        throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
    }
    var streamProvider = new MultipartFormDataStreamProvider(@"C:\Uploads");
    List<string> files = new List<string>();
    try
    {
      // Read the MIME multipart content using the stream provider we just created.
       await Request.Content.ReadAsMultipartAsync(streamProvider);
        //await Request.Content.ReadAsMultipartAsync();

        foreach (MultipartFileData file in streamProvider.FileData)
        {
           files.Add(file.LocalFileName);
        }

        // Send OK Response along with saved file names to the client. 
        return Request.CreateResponse(HttpStatusCode.OK, files);
     }
      catch (Exception e)
     {
       return Request.CreateErrorResponse(HttpStatusCode.InternalServerError, e);
    }
}