I have a problem with setting cookies in an iframe (which loads a site from another domain).
On my site X.COM I load
I experimented a similar problem. A web "parent" page open my "child" website in a jquery fancybox i-frame cross-domain. Not problem at all with Explorer, Chrome, Firefox, Opera and even with Safari (5.8.1) on MAC. But with iPhone, iPad and mini iPad, the session in the i-frame is lost.
That's mean that at every click on an element in the i-frame (web site is in aspx) a new session started.
We solve the problem in a very simple way:
when the parent website start, it call a page in the child site directly (not in an i-frame). In this page I just set a session variable and I redirect to the parent website. Now when the child website is open in an iframe, the session is kept.