HTTP Referer
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[1].
Referer: https://developer.mozilla.org/en-US/docs/Web/JavaScript
Referer: https://example.com/page?q=123
Referer: https://example.com/
主要是以下三种场景，会发送Referer字段[2]。
- 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。