Can you embed a secure IFRAME inside a secure container site?

In a previous post I discussed the security implications of hosting an IFRAME on an insecure container page. The follow-up question is whether it's possible to host a secure IFRAME inside a secure container page, and if all browsers will allow this.

My gut feeling said that this should be possible because the IFRAME has its own browsing context. Browser support is a different question, though, so I conducted a quick experiment.

A quick test on browserstack.com to check if a secure container page can contain an IFRAME which loads another secure page, using IE 6, 7 and 8, and also Safari on iPhone 4S.

The good news is, they all work.

IE6 IE7 IE8 Safari on iPhone4S