How to obtain client browser and operating system information in php

//Display the browser information of the visiting user
echo 'Browser: ' . determinebrowser($Agent) . '';
//Display the visiting user Operating system platform
echo 'Platform: ' . determineplatform($Agent). '';
//Positive expression comparison analysis $_SERVER['HTTP_USER_AGENT'] The string in gets the information of the visiting user's browser
function determinebrowser ($Agent) {
$browseragent=""; //Browser
$browserversion=""; //Browser version
if (ereg(' MSIE ([0-9].[0-9]{1,2})',$Agent,$version)) {
$browserversion=$version[1];
$browseragent="Internet Explorer";
} else if (ereg( 'Opera/([0-9]{1,2}.[0-9]{1,2})',$Agent,$version)) {
$browserversion=$version[1] ;
$browseragent="Opera";
} else if (ereg( 'Firefox/([0-9.]{1,5})',$Agent,$version)) {
$browserversion=$version[1 ];
$browseragent="Firefox";
}else if (ereg( 'Chrome/([0-9.]{1,3})',$Agent,$version)) {
$browserversion=$version[ 1];
$browseragent="Chrome";
}
else if (ereg( 'Safari/([0-9.]{1,3})',$Agent,$version)) {
$browseragent=" Safari";
$browserversion="";
}
else {
$browserversion="";
$browseragent="Unknown";
}
return $browseragent." ".$browserversion;
}
//Similarly obtain the information of the visiting user's browser
//link: http://bbs.it-home.org
function determineplatform ($Agent) {
$browserplatform=='';
 if (eregi('win',$Agent) && strpos($Agent, '95')) {
$browserplatform="Windows 95";
}
elseif (eregi('win 9x',$Agent) && strpos( $Agent, '4.90')) {
$browserplatform="Windows ME";
}
elseif (eregi('win',$Agent) && ereg('98',$Agent)) {
$browserplatform="Windows 98";
}
elseif (eregi('win',$Agent) && eregi('nt 5.0',$Agent)) {
$browserplatform="Windows 2000";
}
elseif (eregi('win', $Agent) && eregi('nt 5.1',$Agent)) {
$browserplatform="Windows XP";
}
elseif (eregi('win',$Agent) && eregi('nt 6.0',$Agent) ) {
$browserplatform="Windows Vista";
}
elseif (eregi('win',$Agent) && eregi('nt 6.1',$Agent)) {
$browserplatform="Windows 7";
}
 elseif (eregi('win',$Agent) && ereg('32',$Agent)) {
$browserplatform="Windows 32";
}
elseif (eregi('win',$Agent) && eregi(' nt',$Agent)) {
$browserplatform="Windows NT";
}elseif (eregi('Mac OS',$Agent)) {
$browserplatform="Mac OS";
}
elseif (eregi(' linux',$Agent)) {
$browserplatform="Linux";
}
elseif (eregi('unix',$Agent)) {
$browserplatform="Unix";
}
elseif (eregi('sun' ,$Agent) && eregi('os',$Agent)) {
$browserplatform="SunOS";
}
elseif (eregi('ibm',$Agent) && eregi('os',$Agent)) {
$browserplatform="IBM OS/2";
}
elseif (eregi('Mac',$Agent) && eregi('PC',$Agent)) {
$browserplatform="Macintosh";
}
elseif ( eregi('PowerPC',$Agent)) {
$browserplatform="PowerPC";
}
elseif (eregi('AIX',$Agent)) {
$browserplatform="AIX";
}
elseif (eregi( 'HPUX',$Agent)) {
$browserplatform="HPUX";
}
elseif (eregi('NetBSD',$Agent)) {
$browserplatform="NetBSD";
}
elseif (eregi('BSD ',$Agent)) {
$browserplatform="BSD";
}
elseif (ereg('OSF1',$Agent)) {
$browserplatform="OSF1";
}
elseif (ereg('IRIX', $Agent)) {
$browserplatform="IRIX";
}
elseif (eregi('FreeBSD',$Agent)) {
$browserplatform="FreeBSD";
}
if ($browserplatform=='') { $browserplatform = "Unknown"; }
return $browserplatform;
}
?>

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