Napsal jsem si tenhle script:
<?php
 include 'error.inc';
 include 'db.inc';
 
  $errorString = "";
 foreach($HTTP_POST_VARS as $varname => $value)
   $formVars[$varname] = trim(clean($value, 50));
  if (empty($formVars["firstName"]))
   $errorString .=
    "\n<br>Name";
  
  if (empty($formVars["surname"]))
   $errorString .=
    "\n<br>surname";
  
  if (empty($formVars["address1"]))
   $errorString .=
    "\n<br>address";	
  
  if (empty($formVars["city"]))
   $errorString .=
    "\n<br>city";	
	
  
  if (empty($formVars["dob"]))
   $errorString .=
    "\n<br>dob";	
	
  
  elseif (!ereg("^([0-9]{2})/([0-9]{2})/([0-9]{4})$",
   $formVars["dob"], $parts))
   $errorString .=
   "\n<br>narozeniny" .
   "ve formatu ddmmrrrr";
 
 
  if (empty($formVars["email"]))
   $errorString .=
    "\n<br>email";   
	
	
 if (!empty($errorString))
 {
 
?>
<head><title>Chyby ve formulari!</title></head>
<body>
<font color="red">
<h1>CHYBY!</h1>
<?=$errorString?>
<br><a href="example.6-5.php"> Návrat </a>
</body>
<?php
  exit;
 }
 
 
 if (!($connection = @ mysql_pconnect($hostName, $unsername, $password)))
	die("Nemohu se připojit k databázi!");
 if (!mysql_select_db($databeseName, $connection))
    showerror();
	
$dob = " \"$parts[3]-$parts[2]-$parts[1]\"";
$query = "INSERT INTRO customer
         set cust_id = NULL, " .
		 "surname = \"" . $formVars["surname"] . "\", " .
		 "firstname = \"" . $formVars["firstName"] . "\", " .
		 "addresslinel = \"" . $formVars["address1"] . "\", " .
		 "city = \"" . $formVars["city"] . "\", " .
		 "email = \"" . $formVars["email"] . "\", " .
		 "birth_date = $dob";
		 
 if (!(@ mysql_query ($query, $connection)))
   showerror();
   
 $custID = mysql_isert_id();
 
 
 header("Location: customer_receipt.php?custID=?custID");
 
 ?>	
a háže mi to error:
Fatal error: Call to undefined function: clean() in /3w/aktualne.cz/h/hackers/test/example.6-6.php on line 11
Už si stím nevím rady! 
Prosím pomoc!