interacting with checkboxes in a php while loop

Having an issue with my to do list check boxes that are displayed from a php while loop. My JQuery seems to add css class to all my check boxes when i check one of them.

Php function:

function get_tasks(){
    $query = query("SELECT *  FROM tasks");

    confirm($query);

    while($row = fetch_array($query)){

        $task_name = $row['task_name'];
        $task_id = $row['task_id'];
        $task_desc =$row['task_description'];
        $date_created = $row['date_created'];

         $tasks = <<<DELIMETER

        <tr>
        <td><input type="checkbox" class="checkBoxes" name="checkBoxArray" value="{$task_id}"> </td>
        <td> <span class="task_name">{$task_name}</span> </td>
        <td> {$task_desc} </td>
        <td> {$date_created} </td>
        <td> <a href='javascript:void(0)' id="delete" class='btn btn-danger delete_link' rel='{$task_id}' ><span class='glyphicon glyphicon-remove'></span></a></td>   </td>

        </tr>


DELIMETER;

echo $tasks;


    }



}

JQuery code to interact with the check boxes.

<script src="http://ift.tt/2eBd7UN"></script>

<script>
        $(document).ready(function(){  

       $('input:checkbox').change(function(){

          if($(this).is(":checked")){

              $('.task_name').addClass("completed"); //adds strike through to show task is completed.
              $('.delete_link').show();

          } else{

              $('.task_name').removeClass("completed");
              $('.delete_link').hide();



          }

       });

    });

    </script>