Get current URL from IFRAME
If you are in the iframe context,
you could do
const currentIframeHref = new URL(document.location.href);
const urlOrigin = currentIframeHref.origin;
const urlFilePath = decodeURIComponent(currentIframeHref.pathname);
If you are in the parent window/frame, then you can use https://stackoverflow.com/a/938195/2305243 's answer, which is
document.getElementById("iframe_id").contentWindow.location.href
If your iframe is from another domain, (cross domain), the other answers are not going to help you... you will simply need to use this:
var currentUrl = document.referrer;
and - here you've got the main url!
For security reasons, you can only get the url for as long as the contents of the iframe, and the referencing javascript, are served from the same domain. As long as that is true, something like this will work:
document.getElementById("iframe_id").contentWindow.location.href
If the two domains are mismatched, you'll run into cross site reference scripting security restrictions.
See also answers to a similar question.