本文實例講述了php強制用戶轉向www域名的方法。分享給大家供大家參考。具體分析如下：

有時候網站的www域名和非www域名都能訪問網站，但是這樣不利于搜索引擎的收錄，會分散網頁的權重，所以希望用戶訪問非www的域名時通過301永久重定向到www域名，例如用戶訪問bitsCN.com會直接轉向www.bitsCN.com，本php代碼考慮了無法通過head重定向的情況，會在頁面上輸出鏈接，讓用戶點擊。

// Install info.:

// Copy and paste these lines into your default index.php or

// the file that get's called if a visitor comes on your

// website...

// read the host from the server environment

$host = $_SERVER["HTTP_HOST"];

// fix host name - we never now... ;-)

$host = strtolower($host);

$host = trim($host);

// This is important:

// Webbrowsers like Firefox are doing their request without

// the port number like "www.bitsCN.com" but some other

// applications send host names like "www.bitsCN.com:80"

$host = str_replace(':80', '', $host);

$host = trim($host);

// if the host is not starting with www. redirect the

// user to the same URL but with www :-)

if ($host != 'www.bitsCN.com'){

// You an also change the "!=" to "==", if you want to force

// the user to use the domain name without the www.

// send status header, so that search engines or other services

// detect that this is a permanent redirect and not a temporary

header('HTTP/1.1 301 Moved Permanently');

// read the URL the user requested:

$url = isset($_SERVER["REQUEST_URI"]) ? $_SERVER["REQUEST_URI"] : '';

// redirect the user to the new destination:

header('Location: http://www.bitsCN.com' . $url);

// Convert "special" chars -- cause we never now... ;-)

$url = htmlspecialchars($url);

// "fallback" link, if the browser is not supporting header redirects

print 'Please click here';

// stop the script execution here

exit;

}

// If the domain is www.bitsCN.com then go on with your PHP code

// of with your website...

// BTW: You need to replace bitsCN.com trough your own domain :-D

希望本文所述對大家的php程序設計有所幫助。

本文原創發布php中文網，轉載請注明出處，感謝您的尊重！

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