PHP返回josn

<?php
$arr=array('name'=>'张三','age'=>19,'sex'=>'男','status'=>'未婚','className'=>'FG18');

$result=json_encode($arr);
echo $result;
?>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <script src="jquery-1.11.1.js"></script>
</head>
<body>
    <input type="button" id="btn1" value="点击ajax提交">
</body>
<script>
    $(function(){
        $('#btn1').click(function(){
            $.ajax({
                url: "admin.php",
                type: "GET",
                dataType: 'json',
                success: function (json) {
                   alert(json.name + "  " + json.age + " " + json.sex);
                }
            });
        })
    });
</script>
</html>