$content_type = 'text/html; charset=utf-8';
-if (stristr ($_SERVER['HTTP_ACCEPT'], 'application/xhtml+xml'))
+if (isset ($_SERVER['HTTP_ACCEPT']) &&
+ stristr ($_SERVER['HTTP_ACCEPT'], 'application/xhtml+xml'))
$content_type = 'application/xhtml+xml; charset=utf-8';
header('Content-Type: ' . $content_type);
else
$style = $cfg['style'];
-if (stristr ($_SERVER['HTTP_ACCEPT'], 'application/xhtml+xml'))
+if (isset ($_SERVER['HTTP_ACCEPT']) &&
+ stristr ($_SERVER['HTTP_ACCEPT'], 'application/xhtml+xml'))
{
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">