JSFiddle - React, Tailwind, and code Playground

HTML

<iframe></iframe>

CSS

body { height: 2000px; }

iframe {
    position:absolute;
    top:0;
    left:0;
    width: 200px;
    height: 200px;
    border:none;
}

#out{
    position: absolute;
    top: 2px;
    left: 2px;
}

JavaScript

var iframe = $( "iframe" )[0],
    iframeWindow = iframe.contentWindow,
    iframeDoc = iframe.contentDocument || iframeWindow.document;

iframeDoc.write("<!doctype html><html><body>");

$( iframeDoc.body ).css({
	height: "2000px",
    background: "blue"
});

console.log( "window height: " + $( window ).height() );
console.log( "iframe window height: " + $( iframeWindow ).height() );