if ( empty($_SERVER['HTTP_USER_AGENT']) ) {
$is_mobile = false;
} elseif ( strpos($_SERVER['HTTP_USER_AGENT'], 'Mobile') !== false // many mobile devices (all iPhone, iPad, etc.)
if ( empty($_SERVER['HTTP_USER_AGENT']) ) {
$is_mobile = false;
} elseif ( strpos($_SERVER['HTTP_USER_AGENT'], 'Mobile') !== false // many mobile devices (all iPhone, iPad, etc.)