оно?
<html>
<head>
<title>example</title>
</head>
<body>
<select class="default">
<option value="default">Select with few options</option>
<option value="apple">Apple</option>
<option value="banana">Banana</option>
<option value="orange">Orange</option>
</select>
<script src="http://code.jquery.com/jquery-1.11.1.min.js"></script>
<script>
var newValue;
$('select').change(function ()
{
if (newValue)
newValue.css('color', 'black');
newValue = $(this).find(':selected');
newValue.css('color', 'red');
});
</script>
</body>
</html>