Resizing an Iframe Using postmessage

Listener on the site that contains the <iframe> element

function(p, d) {

p = window.addEventListener ? "addEventListener" : "attachEvent";

d = function(e) {

if (e.origin !== "http://www.checktheorigin.com") return;

if (typeof e.data === 'object') {

document.getElementById(e.data.frame).style.height = e.data.height + 'px'

}

};

window[p]((window[p] == "attachEvent" ? "onmessage" : "message"), d, false)

})();

Message sender embedded on the page that renders the content for the iframe

(function(s, p, e, n, d, h, q) {

d = document;

s = d.querySelectorAll("label");

p = s.length;

while (p--) {

e = s.item(p);

n = e.textContent;

e.parentNode.classList.contains("required") && (n += "*");

e.nextElementSibling.setAttribute("placeholder", n)

}

h = (function() {

if (parent.postMessage) {

parent.postMessage( {

height: document.getElementById('content').offsetHeight, frame: window.name

}, '*')

}

})();

})()