JSFiddle - React, Tailwind, and code Playground

HTML

<iframe src="http://jsfiddle.net" height="400" />

JavaScript

window.focus(); //force focus on the currenct window;
window.addEventListener('blur', function(e){
    if(document.activeElement == document.querySelector('iframe'))
    {
        alert('Focus Left Current Window and Moved to Iframe / Possible click!');
    }
});