I’m creating a Chrome extension where clicking on its icon in the extension strip will open a popup. I’m iframing my website in this popup; the URL that’s open in the main tab isn’t particularly important for this question. As the user is interacting with the iframed website, it’ll trigger logic in the extension, and I want to have the Chrome extension be able to modify the contents of the iframed website. Of course, when I tried to do this the naive way by having the extension code try to get info about the iframe, I can’t because of the cross-origin nature.