HTMLAnchorElement: attributionSrc property

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The attributionSrc property of the HTMLAnchorElement interface gets and sets the attributionsrc attribute on an <a> element programmatically, reflecting the value of that attribute. attributionsrc specifies that you want the browser to send an Attribution-Reporting-Eligible header. On the server-side this is used to trigger sending an Attribution-Reporting-Register-Source header in the response, to register of a navigation-based attribution source.

The browser stores the source data associated with the navigation-based attribution source (as provided in the Attribution-Reporting-Register-Source response header) when it receives the navigation response.

See the Attribution Reporting API for more details.

Note: <a> elements cannot be used as attribution triggers, only sources.


A string. There are two versions of this property that you can get and set:

  • Empty string, i.e. aElem.attributionSrc="". This specifies that you want the Attribution-Reporting-Eligible header sent to the same server that the href attribute points to. This is fine when you are handling the attribution source registration on the same server.
  • Value containing one or more URLs, for example:
    aElem.attributionSrc =
      "https://a.example/register-source https://b.example/register-source";
    This is useful in cases where the requested resource is not on a server you control, or you just want to handle registering the attribution source on a different server. In this case, you can specify one or more URLs as the value of attributionSrc. When the resource request occurs, the Attribution-Reporting-Eligible header will be sent to the URL(s) specified in attributionSrc in addition to the resource origin. These URLs can then respond with a Attribution-Reporting-Register-Source to register the source.

    Note: Specifying multiple URLs means that multiple attribution sources can be registered on the same feature. You might for example have different campaigns that you are trying to measure the success of, which involve generating different reports on different data.


Setting an empty attributionSrc

<a href="https://shop.example"> Click to visit our shop </a>
const aElem = document.querySelector("a");
aElem.attributionSrc = "";

Setting an attributionSrc containing URLs

<a href="https://ourshop.example"> Click to visit our shop </a>
// encode the URLs in case they contain special characters
// such as '=' that would be improperly parsed.
const encodedUrlA = encodeURIComponent("https://a.example/register-source");
const encodedUrlB = encodeURIComponent("https://b.example/register-source");

const aElem = document.querySelector("a");
aElem.attributionSrc = `${encodedUrlA} ${encodedUrlB}`;


Attribution Reporting
# dom-htmlattributionsrcelementutils-attributionsrc

Browser compatibility

BCD tables only load in the browser

See also