function cleanInput($input) {
 $search = array(
  '@]*?>.*?@si', // Strip out javascript
  '@<[\/\!]*?[^<>]*?>@si', // Strip out HTML tags
  '@
]*?>.*?
@siU', // Strip style tags properly
  '@@' // Strip multi-line comments
 );
  $output = preg_replace($search, '', $input);
  return $output;
 }
function sanitize($input) {
  if (is_array($input)) {
    foreach($input as $var=>$val) {
      $output[$var] = sanitize($val);
    }
  }
  else {
    if (get_magic_quotes_gpc()) {
      $input = stripslashes($input);
    }
    $input = cleanInput($input);
    $output = mysql_real_escape_string($input);
  }
  return $output;
}
// Usage:
$bad_string = "Hi! It's a good day!";
$good_string = sanitize($bad_string);
// $good_string returns "Hi! It\'s a good day!"
// Also use for getting POST/GET variables
$_POST = sanitize($_POST);
$_GET = sanitize($_GET);