JSFiddle - React, Tailwind, and code Playground

HTML

<iframe id="frm" src="javascript:undefined;"></iframe>

JavaScript

// get FRAME
var iWin = document.getElementById('frm').contentWindow,
    iDoc = iWin.document;

// stick something in it to work with
var div = iDoc.createElement('div');
div.id = 'frm_div';
div.textContent = 'foo';
iDoc.body.appendChild(div);

// test if frame has jQuery, no = add it
if( ! iWin.$ ){
    var jq = iDoc.createElement('script');
    jq.type = 'text/javascript';
    jq.src = 'http://ajax.googleapis.com/ajax/libs/jquery/1.8.1/jquery.min.js';
    jq.onload = ready;
    iDoc.head.appendChild(jq);
}else{
    ready();
}

// what we actually want to do in the frame
function ready(){
    var div = iWin['$']('#frm_div')[0];
    div.textContent = 'bar';
}