get-selected.php

<?php
if (isset($_REQUEST["action1"])) {
    $animal = $_REQUEST["animal"];
    echo "Selected animal: $animal";
}
?>
<form method="POST">
  <select name="animal">
    <option value="dog">dog</option>
    <option value="cat">cat</option>
    <option value="cow">cow</option>
    <option value="pig">pig</option>
    <input type="submit" name="action1" value="select animal"/>
  </select>
</form>

<hr>
<?php
if (isset($_REQUEST["action2"])) {
    $colors = $_REQUEST["colors"];
    echo "selected colors:<br>";
    foreach ($colors as $color)
        echo "- $color<br>";
}
?>
<form method="GET">
  <select name="colors[]" multiple>
    <option value="red">red</option>
    <option value="blue">blue</option>
    <option value="green">green</option>
    <input type="submit" name="action2" value="select color"/>
  </select>
</form>