I tried to use some fancy features to hack in a popup.
Embed('https://mydomain.tld/foo.html',0,0,true), which successfully shows my page with buttons, but calling
alert in page load or
onclick gives me an error:
foo.html:16 Ignored call to 'alert()'. The document is sandboxed, and the 'allow-modals' keyword is not set.. Adding content to the embedded document doesn’t make its frame dynamically expand.
The closest I could get to a popup is a checkbox that toggles an embedded video.