Duda formulario

[abimaelrc]

Con javascript.

Código HTML:

<script type="text/javascript">
function bar(){
    obj = document.getElementById('foo');
    alert(obj.options[obj.selectedIndex].value);
}
</script>
<select id="foo" onchange="bar()">
<option value="">[foobar]</option>
<option value="foo">foo</option>
<option value="bar">bar</option>
<option value="baz">baz</option>
<option value="candy">candy</option>
</select>