function detect_browser()
{
    $list = array(
        "Mozilla Firefox"   => "firefox",
        "Internet Explorer" => "msie",
        "Opera"         => "opera",
        "Google Chrome"     => "chrome"
    );

    foreach($list as $name => $match)
    {
        if(preg_match("/".$match."/is",$_SERVER['HTTP_USER_AGENT']))
            break;
    }

    return $name;
}