var url = "http://localhost/mytest/jsonp_php.php?callback=?";
$.getJSON(url, {
  "age": 21,
  "name": "kitty"
}, function (data) {
  alert("name:" + data.name + ", age:" + data.age);
});

<?php 
  $age=$_GET["age"];
  $name=$_GET["name"];
  $jsondata = "{age:$age, name:'$name'}";
  echo $_GET['callback'].'('.$jsondata.')';
?>

$.ajax({
  type: 'GET',
  url: 'http://localhost/mytest/jsonp_php.php',
  dataType: "jsonp",
  jsonp: "callback5",
  jsonpCallback:"flightHandler",
  data: {
    "age": 21,
    "name": "kitty"
  },
  success: function (data) {
    alert("name:" + data.sd + ", age:" + data.aa)
  }
})

<?php
  $age=$_GET["age"];
  $name=$_GET["name"];
  $ary=array("sd"=>"sdfg","aa"=>23);
   $jsondata=json_encode($ary);
  echo $_GET['callback5'].'('.$jsondata.')';
?>