PHP Manual: get

Description

mixed get_browser ( [string user_agent [, bool return_array]] )

get_browser() attempts to determine the capabilities of the user's browser. This is done by looking up the browser's information in the browscap.ini file.

By default, the value of HTTP User-Agent header is used; however, you can alter this (i.e., look up another browser's info) by passing the optional user_agent parameter to get_browser(). You can bypass user_agent parameter with NULL value.

The information is returned in an object, which will contain various data elements representing, for instance, the browser's major and minor version numbers and ID string; TRUE/FALSE values for features such as frames, JavaScript, and cookies; and so forth.

As of PHP 4.3.2, if the optional parameter return_array is TRUE, this function will return an array instead of an object.

Example 1. Listing all information about the users browser

<?php
echo $_SERVER['HTTP_USER_AGENT'] . "\n\n";

$browser = get_browser(null, true);
print_r($browser);
?>

The above example will output something similar to:

Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040803 Firefox/0.9.3

Array
(
    [browser_name_regex] => ^mozilla/5\.0 (windows; .; windows nt 5\.1; .*rv:.*) gecko/.* firefox/0\.9.*$
    [browser_name_pattern] => Mozilla/5.0 (Windows; ?; Windows NT 5.1; *rv:*) Gecko/* Firefox/0.9*
    [parent] => Firefox 0.9
    [platform] => WinXP
    [browser] => Firefox
    [version] => 0.9
    [majorver] => 0
    [minorver] => 9
    [css] => 2
    [frames] => 1
    [iframes] => 1
    [tables] => 1
    [cookies] => 1
    [backgroundsounds] => 
    [vbscript] => 
    [javascript] => 1
    [javaapplets] => 1
    [activexcontrols] => 
    [cdf] => 
    [aol] => 
    [beta] => 1
    [win16] => 
    [crawler] => 
    [stripper] => 
    [wap] => 
    [netclr] => 
)

The cookies value simply means that the browser itself is capable of accepting cookies and does not mean the user has enabled the browser to accept cookies or not. The only way to test if cookies are accepted is to set one with setcookie(), reload, and check for the value.

Note: In order for this to work, your browscap configuration setting in php.ini must point to the correct location of the browscap.ini file on your system.
browscap.ini is not bundled with PHP, but you may find an up-to-date php_browscap.ini file here.
While browscap.ini contains information on many browsers, it relies on user updates to keep the database current. The format of the file is fairly self-explanatory.