set ( 'HTML.Doctype', 'HTML 4.01 Strict' );
$config->set ( 'HTML.Allowed', 'b,a[href],br' );
$config->set ( 'CSS.AllowTricky', true );
$config->set ( 'URI.Disable', true );
$serial = $config->serialize ();
$result = unserialize ( $serial );
$purifier = new HTMLPurifier ( $result );
echo htmlspecialchars ( $purifier->purify ( 'Bold
no formatting' ) );