výber hodnoty pomocí option

<select name="platforma" size="1"> 
  <option value="win">Windows
  <option value="linux">Linux
  <option value="unix">Unix
  <option value="mac">Mac
</select>

        <div>
            <strong>Vyberte uživetele:</strong>
            <form action="#" method="post">
                <select name="select1" size="1" onchange="document.body.className = 'v' + (this.selectedIndex + 1)">
                    <?php
                        include 'config.php';

                            $vypis =  mysql_query("SELECT * FROM uzivatele order by id desc");
                                while($row = mysql_fetch_array($vypis))
                                    {
                                        echo "<option onClick='vyber1();' value='s2'>".$row["uziv_jmeno"]."</option>";
                                    }
                            mysql_close();
                    ?>
                </select>
            </form>
            <script type="text/javascript">
                function vyber1()
                    {
                        if (document.formular1.select1[0].selected) 
                            {
                                document.body.className = 'v1';
                            }
                        else if (document.formular1.select1[1].selected)
                             {
                                 document.body.className = 'v2';
                             }
                        else if (document.formular1.select1[2].selected) 
                            {
                                document.body.className = 'v3';
                            }
                        else if (document.formular1.select1[3].selected) 
                            {
                                document.body.className = 'v4';
                            }
                    }
            </script> 
            <span class="v2">gfhsfgsdfgsfdgsfhdfsdgsfdhsfhgdfgsfhsdfghsfdh</span> 
        </div>