I Have one dropdownlist filled with country list and another dropdownlist empty, I have a 2 buttons > >> 

When I press the > button I want to add a country from country dropdownlist to emptydropdown list ony by one (the ones which are selected) and when I press the >> I want add the countries add to empty dropdownlist. And each time It adds it should be removed from the first dropdown list too. 

I tried:

```
 $("#form_selectednationality_id").add($("#form_nationality_id option:selected"));
 $("#form_nationality_id option:selected").remove();

```

it removes the item succefully but doesn't add anything
Do you have any comment or idea?
thanks.