how to detect internet explorer and firefox using PHP?

Question

how to detect internet explorer and firefox using PHP?

Answer 1

 if (isset($_SERVER['HTTP_USER_AGENT'])) {
   $useragent   = $_SERVER['HTTP_USER_AGENT'];
 }

 if (strlen(strstr($useragent  , 'MSIE')) > 0) {
    $browser = 'internet explorer';
 }else if (strlen(strstr($useragent  , 'Firefox')) > 0) {
    $browser = 'firefox';
 }else{
   $browser = 'others';
 }

 echo $browser;