Update your browser!

I decided to ask Yandex how to determine the visitor's browser (in PHP).
The second link led to a “wonderful” example script.

<?
//

.if(eregi("opera",$HTTP_USER_AGENT))// , $browse = OP
$browser = "OP";

else if(eregi("msie",$HTTP_USER_AGENT))// MSIE, $browse = IE
$browser = "IE";

else if(eregi("Mozilla.[4.]",$HTTP_USER_AGENT))
$browser = "NS";

else if(eregi("Mozilla.[5|6]",$HTTP_USER_AGENT))
$browser = "MO";
else // - , OT
$browser = "OT";
?>
// . . . .

<? if ($browser=="IE") {
echo " Internet Explorer ";// ie, Internet Explorer
}
if ($browser=="OP") {
echo " Opera!
! ";
}
if ($browser=="NS") {
echo " Netscape!
!
";
}
if ($browser=="MO") {
echo " Mozilla! ! ";
}
if ($browser=="OT") {
echo " Browser?";// OT ...
}
?>

Update your browser!

a source