echo Json_encode($result);

$.get(

                'process.php',

                {'p1':'aa','p2':'dd', 'data_type':'json'},

                function(data){

                    var resultJson=jQuery.parseJSON(data);

                    if(resultJson.length>0)

                        alert(resultJson[0][AA];
                        alert(resultJson.A.AA);

                }

      );