Парсинг входящего заголовка 'User-Agent'
в php это apache_request_headers()
Он вернет массив пары ключ-значение
Например:
Array
(
[Host] => www.testing.local
[Connection] => keep-alive
[User-Agent] => Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/532.0 (KHTML, like Gecko) Chrome/4.0.206.1 Safari/532.0
[Cache-Control] => max-age=0
[Accept] => application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
[Accept-Encoding] => gzip,deflate,sdch
[Accept-Language] => en-US,en;q=0.8
[Accept-Charset] => ISO-8859-1,utf-8;q=0.7,*;q=0.3
)