Secure iFrames

Was hoping to get some feedback on what everyone feels are best 
practices around securing iFrames.  I've seen a lot of payment platforms 
moving in this direction (ie. Gumroad, Stripe, Memberful) yet with 
little documentation around "here is the best way to secure the iFrame 
our JavaScript generates".

The best documentation I've seen so far recommends an HTTPS webpage with 
the each link pointing to an HTTPS link as well.  This way when you 
click the link to load a modal / JS for the payment solution it is 
"supposedly" done over HTTPS even though the browser won't present a 
padlock (assuming the hosting page is HTTP).  The other example I've 
seen is a simple HTTP page that contains an HTTP link which in turns 
opens a secure iFrame....which is probably not a good idea since you are 
mixing secure and non-secure content.

Thoughts?



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