JSFiddle - React, Tailwind, and code Playground

HTML

foobar<iframe id="ifr" src="about:blank"></iframe>


<button onclick="var ifr=document.getElementById('ifr'); if ((ifr = ifr.contentDocument || ifr.contentWindow.document)){ifr.open();  ifr.write(snippet);  ifr.close();}">write ifr</button>

CSS

iframe{border:1px solid red;}

JavaScript

var snippet = "<script>document.writeln('test')\<\/script>";