JSFiddle - React, Tailwind, and code Playground

HTML

<iframe id="iframe" src="http://fiddle.jshell.net/"></iframe>
<div id="test">test</div>

CSS

iframe {
    height: 500px;
    width: 800px;
}
#text {
    
}

JavaScript

$( "#test" ).on( "click", function() {
    var iframe = $("#iframe").contents();
    iframe.find('#header').css('background-color', 'red');
    iframe.find('#header').html('My content');
});