JSON error(s) with php backend

This is the least documented thing in jquery what you need to do is alert the actual error in order to debug it. so do the following:

function my_ajax(){
    $.ajax({
         url: '/ajax/goal_ajax.php',
         dataType: 'json',
         success: function( data ){
          // success! :D
          alert('success');
         }, error: function(jqXHR, textStatus, errorThrown){
          // data.responseText is what you want to display, that's your error.
          alert(jqXHR+","+textStatus+","+errorThrown);
         }
    })
    //progressBar.set('value',data.total);
    //document.getElementById('txtCDInfo').innerHTML=txt;
} 

So two things I've done:

Change the name of the function (ajax is kinda a bad name :S) and improved the error reporting.

You should be getting the alert "success" yes. So something is going wrong.

EDIT:

Just noticed another thing, I dont think "../" would be a great way to reference the url, usually its either "/foo/ajax" which will allow you to use this function on any page.

It could be that your PHP script returns an error status code and even though it prints out the correct result, it still fails. I tested your scripts on my system and I got the 'success' alert. Then I changed my PHP script to the following:

<?php
header('Content-type: application/json', true, 401); 
echo '{"items":1000,"mitems":0,"donations":0,"total":1000}';
?>

Note that the third parameter of the header function sets the http response code to 401 - Even though the correct output is sent back to the client; officially, the request has failed because of that status code. After running this code, I got the exact same problem as you.

So in summary, there might be something in your script which is causing a non-fatal error which doesn't show in the output of the script.

Are you defining the MIME type in your HTTP response?

Try adding a Content-type header to the output of your script.

<?php
...
    $output = json_encode(...);
    header('Content-type: application/json');
    echo $output;
...
?>

You can also try using the mimeType parameter in your $.ajax() call to override the response type.

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

Are you running your PHP scripts under Apache or on their own (chmod u+x on the script)? You probably need to use a PHP framework such as Zend, CodeIgniter or CakePHP and define a controller action that handles your AJAX request to have a proper HTTP response.

As the guy above me said, you should be using the json_encode(); function in PHP then echo'ing that output. Make sure you encode an array though:

    <?
      $send = array(
                  'items' => '1000',
                  'mitems' => '0', 
                  'donations' => '0', 
                  'total' => '1000',
                );

      echo json_encode($send);
    ?>