JSON解码不适用于PHP

Question

I have a WAMP server with PHP 5.4.3 version. I encoded the data in JSON by php file below is the code (submit.php).

$username = 'User';
$comment = 'Test comment';
$date = date("Y-m-d G:i:s");  
$image = '/img/sephiroth.png';

  $return = array(
  'username'=> $username,
  'comment' => $comment,
  'date' => $date,
  'image' => $image  );
  echo json_encode($return); 

Now i have a javascript file(script.js).

$.ajax({
            type: "POST",
            url: "submit.php",
            data: dataString,
            cache: false,
            success: function(result){
                    alert(result); //It is showing all the JSON data.
                    $value = result;
                    $data = json_decode($value,true);
                    alert($data);
                        }
           });

I want to decode all the JSON data separately. e.g Username, comment, date, image. So, i can show them on webpage, at the moment all data is coming together. I tried multiple times with multiple options (php array or result.username or result['username'] but no luck.

Now i am getting below error.

ReferenceError: json_decode is not defined
    $data = json_decode($value,true);

Answer 1

you cannot use json_decode in JS json_decode is PHP function

use jQuery.parseJSON(json_data) to parse your json data;

jQuery.parseJSON( result );

Change

$value = result;
$data = json_decode($value,true);

To :

jQuery.parseJSON( result );

http://api.jquery.com/jQuery.parseJSON/