<!doctype html>
<html>
<head>
    <meta charset="utf-8"/>
</head>
<body>
    <select multiple id="s">
        <option value="1" id="one" selected>one</option>
        <option id="two" selected>two</option>
    </select>
<script>
    alert(document.getElementById('s').value);
</script>
</body>
</html>