Microsoft Edge iframe-in-iframe "Access Denied"

[kribblo]

Kind of hard to make a good testcase for this one, because it seems a bit random when it occurs, but anyhow:

My company makes games for the internet, which in turn are included in different web pages, sometimes iframes, sometimes not, sometimes dynamically created, sometimes loaded via an URL, you get the picture.

Sometimes, not always, dynamically created iframes lose the document.domain inheritance on Edge. When this happens, window.frameElement.getAttribute('srcdoc'); gives SCRIPT5: Access Denied.

In the end I solved it by implementing the srcdoc functionality like this instead:

iframe.contentWindow.srcdoc = content;
iframe.src = 'javascript:window["srcdoc"]';

I have no idea why this is allowed and not window.frameElement but there you are.

I thought I'd open this issue (and I could provide a pull request if you want me to) in case you want to cover this edge-case as well. It's possibly rare, but real. It still works on all modern browsers AFAICT