i want values of selected item frokm listbox

urgent please hurry up(simple question)i wnat values of item selected in listbox(<select name=yahoo type=list multiple>) after submnitting form
if i use count($yahoo) or sizeof($yahoo) if giving incorrect values
why it is happening.

Here's an example:

Code:

---

<?php

    if (isset($_POST['submit'])) {
        for ($i = 0; $i < count($_POST['yahoo']); $i++) {
            echo $_POST['yahoo'][$i] . "<br>\n";
        }
    } else {
        echo '<form action="test.php" method="post">
            <select name="yahoo[]" type="list" multiple>
                <option value="one">One</option>
                <option value="two">Two</option>
                <option value="three">Three</option>
            </select><br>
            <input type="submit" name="submit" value=" Submit ">
        </form>';
    }

?>

---