Ajax 500 Internal Server Error

Hi there,

I am trying to utilize ajax-functionality for a plugin I am creating, but get a 500 Internal Server Error when trying to do so. Here is what I am doing:

1. User changes something on plugin-page.
2. The change is registered through JavaScript (jQuery).
3. a jQuery.Post call is made to a function named ajax_callback, as seen below.
4. The call tries to send two variables to the function: ‘caseType’ and ‘data’.
5. ajax_callback checks whether ‘caseType’ is defined, and if it is proceeds with printing ‘data’.

However, step 5 fails, and only the backfire of ajax_callback is printed. The jQuery.Post call looks like this:

$.post(ajaxurl, {
  action: "ajax_callback",
  caseType: "1",
  data: array1
}, function(data) {
  $("#result").html(data);
}, "text");

And the axax_callback looks like this:

add_action('wp_ajax_ajax_callback', 'ajax_callback');
function ajax_callback() {
  if (!$_POST['caseType']) {exit("caseType is not defined");}
  switch ($_POST['caseType']) {
  case "1":
    $data = $_POST['data'];
    print_r($data);
    break;
  case "2":
    $data = $_POST['data'];
    print_r($data);
    break;
}

So basically, ‘caseType’ defines what to do, and ‘data’ is passed on. But why am I getting the backfire from saying “caseType is not defined”? As seen by the JavaScript code, case “1” of the ajax_callback should be invoked, and the ‘data’ printed directly.

Any ideas on what is going wrong?