如何在PHP之前检测用户来自的网站？

在使用PHP访问我的网站之前,如何检测用户来自的网站？

解决方法:

尝试这个：

$_SERVER['HTTP_REFERER']

有关更多信息,请参阅HTTP referrer：

The referrer, or HTTP referrer—also
kNown by the common misspelling
referer that occurs as an HTTP header
field—identifies, from the point of
view of an internet webpage or
resource, the address of the webpage
(commonly the URL, the more generic
URI or the i18n updated IRI) of the
resource that links to it. By checking
the referrer, the new page can see
where the request came from.