<?phpif(isset($_POST['select1'])){    $select1 = $_POST['select1'];    switch ($select1) {        case 'value1':            echo 'this is value1<br/>';            break;        case 'value2':            echo 'value2<br/>';            break;        default:            # code...            break;    }}?> <form action="" method="post">    <select name="select1">        <option value="value1">Value 1</option>        <option value="value2">Value 2</option>    </select>    <input type="submit" name="submit" value="Go"/></form>