fullscreen directive controls whether the current document is allowed to use
Element.requestFullscreen(). When this policy is enabled, the returned
Promise rejects with a
By default, top-level documents and their same-origin child frames can request and enter fullscreen mode. This directive allows or prevents cross-origin frames from using fullscreen mode. This includes same-origin frames.
Note: If both this directive (i.e. via the
allow attribute) and the
allowfullscreen attribute are present on an
<iframe> element, this directive takes precedence. There was a bug whereby the
fullscreen directive didn't work unless the
allowfullscreen attribute was also present, but this has been fixed as of Firefox 80 (bug 1608358).