$_SERVER['HTTP_USER_AGENT']



you can use $_SERVER['HTTP_USER_AGENT'] to find what browser your users are using.

or you can also use this function to find out.

PHP Code:
<?php
$browser = get_browser(null, true);
echo '<pre>';
print_r($browser);
echo '</pre>';
?>


this is example output: 

Array
(
    [browser_name_regex] => ^mozilla/5.0 (windows.*$
    [browser_name_pattern] => Mozilla/5.0 (Windows*
    [parent] => Netscape6
    [platform] => Windows
    [browser] => Netscape
    [version] => 6.0b1
    [majorver] => 6
    [minorver] => 0b1
    [frames] => 1
    [tables] => 1
    [cookies] => 1
    [backgroundsounds] => 
    [vbscript] => 
    [javascript] => 1
    [javaapplets] => 1
    [activexcontrols] => 
    [beta] => 1
    [crawler] => 
    [authenticodeupdate] => 
    [msn] => 
)


hope this helps