input hidden selected
<form>
<select id="dropdown" name="dropdown" onchange="changeHiddenInput(this)">
<option value="j.hotmail.com">Jens</option>
<option value="a.hotmail.com">Adam</option>
<option value="d.homtail.com">Dan</option>
</select>
<input type="hidden" name="hiddenInput" id="hiddenInput" value="" />
</form>
function changeHiddenInput (objDropDown)
{
var objHidden = document.getElementById("hiddenInput");
objHidden.value = objDropDown.value;
}