评论删除无效

I'm trying to perform a delete of a forum comment using Jquery AJAX and PHP(codeigniter) with Datamapper but for some reason no matter what I do nothing happens when I click delete.

If anyone can see the problem that'd be great.

Jquery =

$('button.delete').on('click', function(event) {

    console.log('derp');
    // var comment = $(this).parent('.comment').attr('id');

    // $.post('actions/delete_comment/'+comment);

});

forum post php =

<li class="comment" id="<?=$comment->id ?>">
    <img  src="assets/img/avatars/<?=$comment->user.'.jpg' ?>">
    <p class="username"><?=$comment->user ?></p><p class="commenttime"><?=$comment->date ?></p><br>
    <p><?=$comment->contents ?></p>
    <button class="delete">Delete</button>
</li>

delete php =

public function delete_comment($id){
    $comments = new Forum_comment;
    $comments->get_where(array('id' => $id));
    $comments->delete();
}