function detect_browser($HTTP_USER_AGENT) {
// Браузер и его версия
 if (eregi("(opera) ([0-9]{1,2}.[0-9]{1,3}){0,1}", $HTTP_USER_AGENT, $match) || eregi("(opera/)([0-9]{1,2}.[0-9]{1,3}){0,1}", $HTTP_USER_AGENT, $match)) {
  $browser[name] = "Opera";
  $browser[version] = $match[2];
 }
 elseif (eregi("(konqueror)/([0-9]{1,2}.[0-9]{1,3})", $HTTP_USER_AGENT, $match)) {
  $browser[name] = "Konqueror";
  $browser[version] = $match[2];
 }
 elseif (eregi("(lynx)/([0-9]{1,2}.[0-9]{1,2}.[0-9]{1,2})", $HTTP_USER_AGENT, $match)) {
  $browser[name] = "Lynx";
  $browser[version] = $match[2];
 }
 elseif (eregi("(links) \(([0-9]{1,2}.[0-9]{1,3})", $HTTP_USER_AGENT, $match)) {
  $browser[name] = "Links";
  $browser[version] = $match[2];
 }
 elseif (eregi("(msie) ([0-9]{1,2}.[0-9]{1,3})", $HTTP_USER_AGENT, $match)) {
  $browser[name] = "MSIE";
  $browser[version] = $match[2];
 }
 elseif (eregi("(netscape6)/(6.[0-9]{1,3})", $HTTP_USER_AGENT, $match)) {
  $browser[name] = "Netscape";
  $browser[version] = $match[2];
 }
 elseif (eregi("(mozilla)/([0-9]{1,2}.[0-9]{1,3})", $HTTP_USER_AGENT, $match)) {
  $browser[name] = "Netscape";
  $browser[version] = $match[2];
 }
 elseif (eregi("mozilla/5", $HTTP_USER_AGENT)) {
  $browser[name] = "Netscape";
  $browser[version] = "Unknown";
 }
 elseif (eregi("w3m", $HTTP_USER_AGENT)) {
  $browser[name] = "w3m";
  $browser[version] = "Unknown";
 }
 else {
  $browser[name] = "Unknown";
  $browser[version] = "Unknown";
 }

// Операционная система
 if (eregi("linux", $HTTP_USER_AGENT)) $browser[os] = "Linux";
 elseif (eregi("win32", $HTTP_USER_AGENT)) $browser[os] = "Windows";
 elseif ((eregi("(win)([0-9]{2})", $HTTP_USER_AGENT, $match)) || (eregi("(windows) ([0-9]{2})", $HTTP_USER_AGENT, $match))) $browser[os] = "Windows ".$match[2];
 elseif (eregi("(winnt)([0-9]{1,2}.[0-9]{1,2}){0,1}", $HTTP_USER_AGENT, $match)) $browser[os] = "Windows NT ".$match[2];
 elseif (eregi("(windows nt)( ){0,1}([0-9]{1,2}.[0-9]{1,2}){0,1}", $HTTP_USER_AGENT, $match)) $browser[os] = "Windows NT ".$match[3];
 elseif (eregi("mac", $HTTP_USER_AGENT)) $browser[os] = "Macintosh";
 elseif (eregi("(sunos) ([0-9]{1,2}.[0-9]{1,2}){0,1}", $HTTP_USER_AGENT, $match)) $browser[os] = "SunOS ".$match[2];
 elseif (eregi("(beos) r([0-9]{1,2}.[0-9]{1,2}){0,1}", $HTTP_USER_AGENT, $match)) $browser[os] = "BeOS ".$match[2];
 elseif (eregi("freebsd", $HTTP_USER_AGENT)) $browser[os] = "FreeBSD";
 elseif (eregi("openbsd", $HTTP_USER_AGENT)) $browser[os] = "OpenBSD";
 elseif (eregi("irix", $HTTP_USER_AGENT)) $browser[os] = "IRIX";
 elseif (eregi("os/2", $HTTP_USER_AGENT)) $browser[os] = "OS/2";
 elseif (eregi("plan9", $HTTP_USER_AGENT)) $browser[os] = "Plan9";
 elseif (eregi("unix", $HTTP_USER_AGENT) || eregi("hp-ux", $HTTP_USER_AGENT)) $browser[os] = "Unix";
 elseif (eregi("osf", $HTTP_USER_AGENT)) $browser[os] = "OSF";
 else $browser[os] = "Unknown";

 return $browser;
}

$browser = detect_browser($HTTP_USER_AGENT);
echo "Браузер: ".$browser[name]." ".$browser[version]."\nОперационная система: ".$browser[os];
//Создатель: Mal Hack(Vingrad)