JSFiddle - React, Tailwind, and code Playground

HTML

<iframe id="target" src="https://example.com/"></iframe>

JavaScript

try {
    var x = document.getElementById("target").contentWindow.location.href;
    if (x == "https://example.com/") {
    		alert("Your browser is not enforcing the SOP! Change your browser and all passwords asap");
    }
    else {
    	alert("Your browser appears to be fine");
    }
}
catch (e) {
    alert("Your browser appears to be fine");
}