a - referrerpolicy : no-referrer | no-referrer-when-downgrade | origin | origin-when-cross-origin | same-origin | strict-origin-when-cross-origin | unsafe-url

The referrerpolicy attribute specifies which referrer information to send when the user clicks on the hyperlink.

Attribute Values

no-referrer

No referrer information is sent.

no-referrer-when-downgrade

Default. Sends the origin, path, and query string if the protocol security level stays the same or is higher (HTTP to HTTP, HTTPS to HTTPS, HTTP to HTTPS is ok). Sends nothing to less secure level (HTTPS to HTTP is not ok).

origin

Sends the origin (scheme, host, and port) of the document.

origin-when-cross-origin

Sends the origin of the document for cross-origin request. Sends the origin, path, and query string for same-origin request

same-origin

Sends a referrer for same-origin request. Sends no referrer for cross-origin request

strict-origin-when-cross-origin

Sends the origin if the protocol security level stays the same or is higher (HTTP to HTTP, HTTPS to HTTPS, and HTTP to HTTPS is ok). Sends nothing to less secure level (HTTPS to HTTP).

unsafe-url

Sends the origin, path, and query string (regardless of security). Use this value carefully !