查看“︁HTTP Referer”︁的源代码

The Referer HTTP request header contains the absolute or partial address from which a resource has been requested. The Referer header allows a server to identify referring pages that people are visiting from or where requested resources are being used. This data can be used for analytics, logging, optimized caching, and more<ref>https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Referer</ref>.

<syntaxhighlight lang="HTTP">
Referer: https://developer.mozilla.org/en-US/docs/Web/JavaScript
Referer: https://example.com/page?q=123
Referer: https://example.com/
</syntaxhighlight>

主要是以下三种场景，会发送Referer字段<ref>https://www.ruanyifeng.com/blog/2019/06/http-referer.html</ref>。

* 用户点击网页上的链接。
* 用户发送表单。
* 网页加载静态资源，比如加载图片、脚本、样式。

== Referrer Policy ==
The original header name Referer is a misspelling of the word "'''referrer'''". The Referrer-Policy header does not share this misspelling.

<syntaxhighlight lang="HTTP">
Referrer-Policy: no-referrer
Referrer-Policy: no-referrer-when-downgrade
Referrer-Policy: origin
Referrer-Policy: origin-when-cross-origin
Referrer-Policy: same-origin
Referrer-Policy: strict-origin
Referrer-Policy: strict-origin-when-cross-origin
Referrer-Policy: unsafe-url
</syntaxhighlight>

== Referer and HTTPS ==


[[Category:Network]]
[[Category:HTTP]]
[[Category:RFC]]
[[Category:Protocol]]