The allow property of the HTMLIFrameElement interface indicates the Permissions Policy specified for this <iframe> element. The policy defines what features are available to the <iframe> element (for example, access to the microphone, camera, battery, web-share, etc.) based on the origin of the request.
The Permissions Policy specified by the allow attribute implements a further restriction on top of the policy specified in the Permissions-Policy header. It doesn't replace it.
See <iframe>'s Permissions Policy syntax for more details.
It reflects the allow attribute of the <iframe> element.
A string indicates the Permissions Policy specified for this <iframe> element, each policy must be separated by space.
<iframe
id="el"
src="https://example.com"
allow="geolocation 'self' https://a.example.com https://b.example.com; fullscreen 'none'"></iframe>const el = document.getElementById("el");
console.log(el.allow); // Output: "geolocation 'self' https://a.example.com https://b.example.com; fullscreen 'none'"See Permissions Policy in <iframe> element for more available examples.