<iframe sandbox src="http://attacker.com/untrusted.html"></iframe>
<iframe sandbox="allow-scripts allow-forms" src="http://attacker.com/untrusted.html"></iframe>
if ("sandbox" in document.createElement("iframe")) { // This browser supports @sandbox. We can sandbox untrustedcontent with confidence.}