转载自：http://levi.cg.am/?p=3393

以下代码来自wordpress (/wp-include/vars.php)：

// Simple browser detection
$is_lynx = $is_gecko = $is_winIE = $is_macIE = $is_opera = $is_NS4 = $is_safari = $is_chrome = $is_iphone = false;
 
if ( isset($_SERVER['HTTP_USER_AGENT']) ) {
    if ( strpos($_SERVER['HTTP_USER_AGENT'], 'Lynx') !== false ) {
        $is_lynx = true;
    } elseif ( stripos($_SERVER['HTTP_USER_AGENT'], 'chrome') !== false ) {
        if ( stripos( $_SERVER['HTTP_USER_AGENT'], 'chromeframe' ) !== false ) {
            $is_admin = is_admin();
            /**
             * Filter whether Google Chrome Frame should be used, if available.
             *
             * @since 3.2.0
             *
             * @param bool $is_admin Whether to use the Google Chrome Frame. Default is the value of is_admin().
             */
            if ( $is_chrome = apply_filters( 'use_google_chrome_frame', $is_admin ) )
                header( 'X-UA-Compatible: chrome=1' );
            $is_winIE = ! $is_chrome;
        } else {
            $is_chrome = true;
        }
    } elseif ( stripos($_SERVER['HTTP_USER_AGENT'], 'safari') !== false ) {
        $is_safari = true;
    } elseif ( ( strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE') !== false || strpos($_SERVER['HTTP_USER_AGENT'], 'Trident') !== false ) && strpos($_SERVER['HTTP_USER_AGENT'], 'Win') !== false ) {
        $is_winIE = true;
    } elseif ( strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE') !== false && strpos($_SERVER['HTTP_USER_AGENT'], 'Mac') !== false ) {
        $is_macIE = true;
    } elseif ( strpos($_SERVER['HTTP_USER_AGENT'], 'Gecko') !== false ) {
        $is_gecko = true;
    } elseif ( strpos($_SERVER['HTTP_USER_AGENT'], 'Opera') !== false ) {
        $is_opera = true;
    } elseif ( strpos($_SERVER['HTTP_USER_AGENT'], 'Nav') !== false && strpos($_SERVER['HTTP_USER_AGENT'], 'Mozilla/4.') !== false ) {
        $is_NS4 = true;
    }
}
 
if ( $is_safari && stripos($_SERVER['HTTP_USER_AGENT'], 'mobile') !== false )
    $is_iphone = true;
 
$is_IE = ( $is_macIE || $is_winIE );
 
// Server detection
 
/**
 * Whether the server software is Apache or something else
 * @global bool $is_apache
 */
$is_apache = (strpos($_SERVER['SERVER_SOFTWARE'], 'Apache') !== false || strpos($_SERVER['SERVER_SOFTWARE'], 'LiteSpeed') !== false);
 
/**
 * Whether the server software is Nginx or something else
 * @global bool $is_nginx
 */
$is_nginx = (strpos($_SERVER['SERVER_SOFTWARE'], 'nginx') !== false);
 
/**
 * Whether the server software is IIS or something else
 * @global bool $is_IIS
 */
$is_IIS = !$is_apache && (strpos($_SERVER['SERVER_SOFTWARE'], 'Microsoft-IIS') !== false || strpos($_SERVER['SERVER_SOFTWARE'], 'ExpressionDevServer') !== false);
 
/**
 * Whether the server software is IIS 7.X or greater
 * @global bool $is_iis7
 */
$is_iis7 = $is_IIS && intval( substr( $_SERVER['SERVER_SOFTWARE'], strpos( $_SERVER['SERVER_SOFTWARE'], 'Microsoft-IIS/' ) + 14 ) ) >= 7;
 
/**
 * Test if the current browser runs on a mobile device (smart phone, tablet, etc.)
 *
 * @return bool true|false
 */
function wp_is_mobile() {
    static $is_mobile;
 
    if ( isset($is_mobile) )
        return $is_mobile;
 
    if ( empty($_SERVER['HTTP_USER_AGENT']) ) {
        $is_mobile = false;
    } elseif ( strpos($_SERVER['HTTP_USER_AGENT'], 'Mobile') !== false // many mobile devices (all iPhone, iPad, etc.)
        || strpos($_SERVER['HTTP_USER_AGENT'], 'Android') !== false
        || strpos($_SERVER['HTTP_USER_AGENT'], 'Silk/') !== false
        || strpos($_SERVER['HTTP_USER_AGENT'], 'Kindle') !== false
        || strpos($_SERVER['HTTP_USER_AGENT'], 'BlackBerry') !== false
        || strpos($_SERVER['HTTP_USER_AGENT'], 'Opera Mini') !== false
        || strpos($_SERVER['HTTP_USER_AGENT'], 'Opera Mobi') !== false ) {
            $is_mobile = true;
    } else {
        $is_mobile = false;
    }
 
    return $is_mobile;
}

判断php运行环境的函数php_sapi_name()

• 在apache环境下面输出的结果是“apache2handler”；
• 在nginx环境下输入的结果是“fpm-fcgi”；
• 在cgi模式下输出的结果是“cgi-fcgi”；
• 要是在命令行模式下面运行的话，那么输出的结果是：”cli”