why does [XMLHttpReequest] object Message come?

why does [XMLHttpReequest] object Message come?


I am calling below javascript method from code behind then,
why does [Object XMLHttpReequest] Message come?

function SendMsg() {
      var user = document.getElementById('<%=User.ClientID %>');
      var val = user.value;
      var nonrno = 1234;
      var rno = 123;
     
        var options = {
          type: "POST",
          url: "Test.aspx/SendMessage",
          data: "{'toMailAddress':'" + val + "','rno':'" + rno+ "', 'nonrno':'" + nonrno+ "'}",
          contentType: "application/json; charset=utf-8",
          dataType: "json",
          success: function (response) {
             var val1 = response.d;
             alert(val1);
             if (val1 == "1") {
               // Below code is used to close the window, if message has been sent to the user sucessfully.
               var windowObj = window.self;
               windowObj.opener = window.self;
               windowObj.close();
             }
          },
          error: function (result) {
            alert("Error in " + result);
          }
        };
        //Call the PageMethods
        $.ajax(options);
      }