Method call with ajax in aspx.cs from aspx

I am trying to call a method on my aspx page. This method was found in the aspx.cs page, but it throws an error. Do you know what happened please?

ajax script

<script type="text/javascript">
     function OnSucceeded(response) {
         alert(response);
     }
     function OnFailed(error) {
         alert(error);
     }         //Default.aspx
     function insertMarker() {
         var usernameName = 'username';
         var usernameVal = document.getElementById('<%=hdnUsername.ClientID%>').value;

         var latitudeName = 'latitudeStr';
         var latitudeVal = document.getElementById('<%=hdnMarkerLatitude.ClientID%>').value;

         var longituteName = 'longitudeStr';
         var longitudeVal = document.getElementById('<%=hdnMarkerLongitude.ClientID%>').value;

         var iconName = 'markerIcon';
         var iconVal;
         if (document.getElementById('blueMarker').checked) {
             iconVal = 'images/blueMarker.png';
         }
         if (document.getElementById('greenMarker').checked) {
             iconVal = 'images/greenMarker.png'
         }
         if (document.getElementById('pinkMarker').checked) {
             iconVal = 'images/pinkMarker.png';
         }

         var titleName = 'name';
         var titleVal = document.getElementById('<%=title.ClientID%>').value;

         var descriptionName = 'description';
         var descriptionVal = document.getElementById('<%=description.ClientID%>').value;

         $.ajax({
             type: "POST",
             url: "mapping.aspx/insertNewMarker",
             data: {"username" : usernameVal, "longitudeStr":longitudeVal, "latitudeStr" :latitudeVal, "markerIcon":iconVal, "name" : titleVal, "description" :descriptionVal},
             contentType: 'application/json; charset=utf-8',
             dataType: 'json',
             error: function (XMLHttpRequest, textStatus, errorThrown) {
                 alert("Request: " + XMLHttpRequest.toString() + "\n\nStatus: " + textStatus + "\n\nError: " + errorThrown);
             },
             success: function (result) {
                 alert("We returned: " + result.d);
             }
         });
     }

     </script>

      

        
        
        
      

    

Site design Save marker title Description                                                                                                    

                                                                                                     Save                     

The Aspx.cs method.

[ScriptService]
public partial class mapping: System.Web.UI.Page
{
    [WebMethod]
    private static void insertNewMarker(string username, string longitudeStr, string latitudeStr,  string markerIcon, string name, string description)
    {

       //My Code
    }


}