HTMLFencedFrameElement: config property

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

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

The config property of the HTMLFencedFrameElement contains a FencedFrameConfig object, which represents the navigation of a <fencedframe>, i.e., what content will be displayed in it. A FencedFrameConfig is returned from a source such as the Protected Audience API.

Value

The value of config is initially null.

When its value is set to a FencedFrameConfig object instance, the FencedFrameConfig's internal properties (for example mappedURL) determine what is loaded inside the associated <fencedframe>. In addition:

The navigation type will be "replace" (see NavigateEvent.navigationType), meaning that the current history entry is replaced with the new entry, rather adding a new history entry for it.
The navigation's Referrer-Policy is set to "no-referrer".

Examples

To set what content will be shown in a <fencedframe>, a utilizing API (such as Protected Audience or Shared Storage) generates a FencedFrameConfig object, which is then set as the value of the <fencedframe>'s config property.

The following example gets a FencedFrameConfig from a Protected Audience API's ad auction, which is then used to display the winning ad in a <fencedframe>:

js
const frameConfig = await navigator.runAdAuction({
  // … auction configuration
  resolveToConfig: true,
});

const frame = document.createElement("fencedframe");
frame.config = frameConfig;

Note: resolveToConfig: true must be passed in to the runAdAuction() call to obtain a FencedFrameConfig object. If it is not set, the resulting Promise will resolve to a URN that can only be used in an <iframe>.