As pointed out by Sastry_kunapuli, you are adding the items on client side, the server has no idea about them, so you are getting count = 0 at server side.
If you must do it this way, then here is a way:
1. Add a hidden input field in the form.
<input type="hidden" name="added_to_list" id="added_to_list" value=""></input>
2. Before submitting the form to the server, populate the hidden input field with the items added to the list box at client side. Use some delimiter between entries.
3. On the server, read the hidden input field to retrieve the added items, separating on the delimiter.