<select name="corporation">
<option value="1">corporation1</option>
<option value="2">corporation2</option>
<option value="3">corporation3</option>
</select>
$("[name='corporation']").val(3); //选中corporation3
<select name="corporation">
<option value="1">corporation1</option>
<option value="2">corporation2</option>
<option value="3">corporation3</option>
</select>
$("[name='corporation']").val(3); //选中corporation3