input hidden selected

1 <form>
2    <select id="dropdown" name="dropdown" onchange="changeHiddenInput(this)">
3        <option value="j.hotmail.com">Jens</option>
4        <option value="a.hotmail.com">Adam</option>
5        <option value="d.homtail.com">Dan</option>
6    </select>
7    <input type="hidden" name="hiddenInput" id="hiddenInput" value="" />
8 </form>
9
10    function changeHiddenInput (objDropDown)
11    {
12        var objHidden = document.getElementById("hiddenInput");
13        objHidden.value = objDropDown.value; 
14    }   
15