I have a video in Iframe format in the TAdvWebBrowser. When I click on a fullscreen button nothing happens.
var HTML:='<iframe src="'+URL+'"frameborder="0" allow="autoplay; fullscreen; picture-in-picture" style="position:absolute;top:0;left:0;width:100%;height:100%;"</iframe>';
WebBrowser.LoadHTML(HTML);
I need the video show fullscreen. Is this possible?

In order to show video in FullScreen you need to do the following
EDIT: Looking at TAdvWebBrowser developer guide it doesn't sem that
TAdvWebBrowsersupports detecting when a HTML element of a web page is entering or leaving FullScreen mode.