Try this inside the iframe. It will alert the parent window's location URL.
alert(document.referrer);
Domanda
I know it's a security issue. But is there any way in HTML5. Cause I seen the below code opens a window with the parents URL in tweet box
<iframe src="https://platform.twitter.com/widgets/tweet_button.html"
style="border: 0; width:130px; height:20px;"></iframe>
Soluzione
Try this inside the iframe. It will alert the parent window's location URL.
alert(document.referrer);
Altri suggerimenti
Give this JavaScript a go
var referrer = document.referrer;
console.log(referrer);
Hopefully it works for your purpose. More info on document.referer here if you want to know more:
https://developer.mozilla.org/en-US/docs/Web/API/document.referrer