SO Question
http://stackoverflow.com/questions/7373058
HTML
<select id="sel">
<option>Cat</option>
<option>Dog</option>
<option>Fish</option>
</select>
JavaScript
$('#sel').val('Fish')
<select id="sel">
<option>Cat</option>
<option>Dog</option>
<option>Fish</option>
</select>
$('#sel').val('Fish')