[Shaci]

<script type="text/javascript" src="jquery-1.3.2.js"></script>

<script type='text/javascript'>
$(function(){
    $('.effectTypes').change(function (){
        var selected = $(this).find('option[selected]');
        if(selected.attr('class') == 'yes'){ alert('да')};
        if(selected.attr('class') == 'no'){ alert('нет')};
    })
});
</script>

<select class='effectTypes' size=1' >
<option class='yes'>Да</option>
<option class='no'>Нет</option>
</select>

<select class='effectTypes' size=1' >
<option class='yes'>Да</option>
<option class='no'>Нет</option>
</select>