JSFiddle - React, Tailwind, and code Playground

HTML

<iframe id="iframe1" src="http://www.nu.nl" ></iframe>
<iframe id="iframe2" src="http://www.tweakers.net" ></iframe>

CSS

#iframe1 {
    width:49.5%;
    height: 100%;
    position: fixed;
}
#iframe2 {
    width:49.5%;
    height: 100%;
    right: 0;
    position: fixed;
}
html, body, iframe {
    margin: 0 0 0 0;
    padding: 0 0 0 0;
    overflow:hidden;
}