Question

my code is some thing like this , and in success result msg.d is undefined . i think it is related to formdata as value that is passed to jquery ajax . but i dont know can i resolve it .what is wrong with that ?!

  var files = event.originalEvent.dataTransfer.files;   // i get it in drop event 
  var data = new FormData();

  jQuery.each(files, function (i, file) {
    data.append('file-' + i, file);
  });

  $.ajax({
    type: "POST",
    url: parameters.Url,
    contentType: false,
    processData: false,
    data: data,
    success: function (msg) {        //my return value from webservice is just "hello"
      alert(msg.d);
    }
  });
 }

Answer 1

from your above comment can understand that,
You are actually returning just a string from your server side. And in your client side you are trying to alert an argument ‘d’ from the ajax return. This d is not at all present.

and when you alert message you are getting message [object XMLDocument]. this XML element can change to string if you specify ‘dataType: “text”,’ in your ajax call.

So please try like this.

  $.ajax({
    type: "POST",
    url: parameters.Url,
    data: data,
    dataType: "text",
    success: function (msg) {       
      alert(msg);
    }
  });

Hope this will work fine for you.