Detect onclick event in iframe

gistfile1.txt

var clickIframe = window.setInterval(checkFocus, 100);
var i = 0;

function checkFocus() {
  if(document.activeElement == document.getElementById("ifr")) {
  	console.log("clicked "+(i++));
  	window.focus();
   }
}

// https://stackoverflow.com/questions/29337304/how-to-detect-a-click-inside-of-an-iframe-cross-domain-aka-prevent-click-frau