campi obbligatori in un form

[phoenixweb]

<?php

function checkmail ($email) 
{ 
if (!eregi("^[a-z0-9][_.a-z0-9-]+@([a-z0-9][0-9a-z-]+.)+([a-z]{2,4})$",$email)) return false; 
else return true; 
} 

$nome = isset($_POST['nome']) && trim($_POST['nome']) != '' ? trim($_POST['nome']) : false; 
$cognome = isset($_POST['cognome']) && trim($_POST['cognome']) != '' ? trim($_POST['cognome']) : false; 
$email = isset($_POST['email']) && trim($_POST['email']) != '' ? trim($_POST['email']) : false; 

if ($email && !check_mail($email)) $email = false;




echo " 
<form action=\"".basename($_SERVER['PHP_SELF'])."\" method=\"post\"> 
nome: <input type=\"text\" name=\"nome\" value=\"$nome\"> ".($nome === false ? "<font color=red>campo obbligatorio</font>" : "")." 
cognome : <input type=\"text\" name=\"cognome\" value=\"$cognome\"> ".($cognome === false ? "<font color=red>campo obbligatorio</font>" : "")." 
e-mail : <input type=\"text\" name=\"email\" value=\"$email\"> ".($email === false ? "<font color=red>campo obbligatorio</font>" : "")." 
<input type=\"submit\"> 

</form>"; 
?>