put your
var res
in
Sys.Serialization.JavaScriptSerializer.serialize();
after that try your code...
$.ajax({
type: "POST",
contentType: "application/json",
url: "HuntableWebService.asmx/uploadfile",
data: "{'res':'" + Sys.Serialization.JavaScriptSerializer.serialize(res) + "'}",
dataType: "JSON",
async: true,
success: function (response) {
alert(response.d);
}
});