PHP如何从选择菜单中显示元素

How can I display other elements from a table when I choose an element from a select menu? I have tried to do something, as you can see in the link below, but I don't see anything :(

http://faous.net/test/profile/page1.php

<html>
<header>
    <title>test PHP</title>
</header>
<body>

    <h1>Formulaire</h1>
    <form action="<?php echo $_SERVER['PHP_SELF'];?>" method="get">
    <?php
        echo "<select name='sub1'>";
        while($row=mysql_fetch_array($result)){

            echo "<option value='" . $row['nom'] . "'>" . $row['nom'] . "</option>";
        }

        echo "</select>";
        echo "<br />";
        $result2=mysql_query($sql);
        $base=mysql_fetch_array($result2);
        //$nnnn= $_GET["nom"];
        //$aaaa=$_GET["base"];
        //$bbbb=$_GET["hauteur"];
        //$cccc=$_GET["rayon"];
        $nnnn = $_GET[$row];
        $aaaa = $_GET["base"];
        $bbbb = $_GET["hauteur"];
        $cccc = $_GET["rayon"];

        echo "Nom: $nnnn <br /> Base: $aaaa <br />  Hauteur: $bbbb<br />  Rayon: $cccc";
        echo "<br /> ";

    ?>
    </form> 

</body>
</html>

<?php
    mysql_close($link);
?>

You have to submit your form on change of select like this,

<select onchange="this.form.submit()">

In your case its,

echo "<select name='sub1' onchange='this.form.submit()'>";

mysql_* are deprecated, use mysqli_* or PDO instead


These lines are completely wrong

$result2=mysql_query($sql);// what is $sql here??
$base=mysql_fetch_array($result2);

$nnnn = $_GET[$row];// what is $row??
$aaaa = $_GET["base"]; // where is the form element with name base??
$bbbb = $_GET["hauteur"]; // where is the form element with name hauteur??
$cccc = $_GET["rayon"]; // where is the form element with name rayon??