This way
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title></title>
    <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
    <script type="text/javascript">
        $(document).ready(function () {
            $("select").change(function () {
                $(this).find('option').css('color', '#222');
                $(this).find('option:selected').css('color', '#a1c3d2');
            });
        });
    </script>
</head>
<body>
    <form id="form1">
    <select>
        <option value="1">1</option>
        <option value="2">2</option>
        <option value="3">3</option>
    </select>
    </form>
</body>
</html>
 
Demo