HTMLScriptElement: referrerPolicy property

Baseline Widely available *

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2020.

* Some parts of this feature may have varying levels of support.

The referrerPolicy property of the HTMLScriptElement interface reflects the HTML referrerpolicy of the <script> element, which defines how the referrer is set when fetching the script and any scripts it imports.

Value

A string; one of the following:

no-referrer

The Referer header will be omitted entirely. No referrer information is sent along with requests.

no-referrer-when-downgrade

The URL is sent as a referrer when the protocol security level stays the same (e.g.HTTP→HTTP, HTTPS→HTTPS), but isn't sent to a less secure destination (e.g., HTTPS→HTTP).

origin

Only send the origin of the document as the referrer in all cases. The document https://example.com/page.html will send the referrer https://example.com/.

origin-when-cross-origin

Send a full URL when performing a same-origin request, but only send the origin of the document for other cases.

same-origin

A referrer will be sent for same-site origins, but cross-origin requests will contain no referrer information.

strict-origin

Only send the origin of the document as the referrer when the protocol security level stays the same (e.g., HTTPS→HTTPS), but don't send it to a less secure destination (e.g., HTTPS→HTTP).

strict-origin-when-cross-origin (default)

This is the user agent's default behavior if no policy is specified. Send a full URL when performing a same-origin request, only send the origin when the protocol security level stays the same (e.g., HTTPS→HTTPS), and send no header to a less secure destination (e.g., HTTPS→HTTP).

unsafe-url

Send a full URL when performing a same-origin or cross-origin request. This policy will leak origins and paths from TLS-protected resources to insecure origins. Carefully consider the impact of this setting.

Note: An empty string value ("") is both the default value, and a fallback value if referrerpolicy is not supported. If referrerpolicy is not explicitly specified on the <script> element, it will adopt a higher-level referrer policy, i.e., one set on the whole document or domain. If a higher-level policy is not available, the empty string is treated as being equivalent to no-referrer-when-downgrade.

Examples

js
const scriptElem = document.createElement("script");
scriptElem.src = "/";
scriptElem.referrerPolicy = "unsafe-url";
document.body.appendChild(scriptElem);