How to find the URL of a page in an iframe?
My answer to How to find the URL of a page in an iframe? on Quora
You can’t, as this would be a security and privacy violation. Imagine an evil website which loads up Google in a full page iframe and then tracks what the unsuspecting user searches for and clicks on.
The only way you could achieve this is if the pages within the iframe were deliberately collaborating with you—for example, you open up a page in an iframe of www.example.org?tracker=specialcode and example.org has code which sends information on each subsequent page visited back to your server. Even then, the tracking would stop working once the user clicked a link to a page not hosted on example.org