jquery - Pass checkbox values into an array using ajax to php -

i needing passing checkbox values array using ajax , retrieving values in controller. following code not working. receive error: "invalid argument supplied foreach()". var_dump gives string(42) "educator_classes[]=1&educator_classes;[]=3

thanks can provide.

my html form input:

<input type="checkbox" id="educator_classes[]" name="educator_classes" class="educator_classes" value="<?php echo $class_number; ?>"/> 

my jquery:

$("#send_invite").click(function() {     var form_data = {         opportunity_id: $('#opportunity_id').val(),         educator_id: $('#educator_id').val(),         educator_classes: $('#educator_classes:checked').serialize(),         ajax: '1'     };      $.ajax({         url: "<?php echo site_url('schedule/update_educator_class'); ?>",         type: 'post',         data: form_data,         success: function(data) {             $('#response').html(data);         }     });      return false; }) 

my controller:

function update_educator_class() {     $educator_id = $this->input->post('educator_id');     $opportunity_id = $this->input->post('opportunity_id');     $educator_classes = $this->input->post('educator_classes');      foreach($educator_classes $educator_class):         $this->ion_auth_model->update_educator_class($opportunity_id, $educator_class, $educator_id);     endforeach; } 

you have use [] name attribute , not id, otherwise can't act array

<input type="checkbox" id="educator_classes" name="educator_classes[]" class="educator_classes" value="<?php echo $class_number; ?>"/> 

and jquery code can simpler:

$("#send_invite").click(function() {     var form_data = $(this).closest('form).serialize();     form_data['ajax'] = 1;      $.ajax({         url: "<?php echo site_url('schedule/update_educator_class'); ?>",         type: 'post',         data: form_data,         success: function(data) {             $('#response').html(data);         }     });      return false; }); 

to debut what's passed $educator_classes can this:

var_export($educator_classes);