JSFiddle - React, Tailwind, and code Playground

JavaScript

var iframe = document.createElement('iframe');
iframe.onload = function (){
    try {
        var
           win = iframe.contentWindow,
           doc = win.document,
           json = doc.body.innerHTML
        ;
        alert((new Function('return ('+json+')'))().foo);
    } catch (e){ }
};
iframe.src = '//local.git/index.php?step=1';
document.body.appendChild(iframe);