$from = array("'", "\"", "%", "<", ">", ";");
$to   = array(" ", " ", " /100 ", " LT ", " GT ", " ");

foreach ($_POST as $k=>$v)
{
        $_POST[$k] = str_replace($from, $to, $_POST[$k]);
}

foreach ($_GET as $k=>$v)
{
        $_GET[$k] = str_replace($from, $to, $_GET[$k]);
}

foreach ($_REQUEST as $k=>$v)
{
        $_REQUEST[$k] = str_replace($from, $to, $_REQUEST[$k]);
}

foreach ($_COOKIE as $k=>$v)
{
        $_COOKIE[$k] = str_replace($from, $to, $_COOKIE[$k]);
}