JSFiddle - React, Tailwind, and code Playground
HTML
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>contents demo</title>
<script src="https://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
<iframe src="https://api.jquery.com/" width="80%" height="600" id="frameDemo"></iframe>
<script>
$( "#frameDemo" ).contents().find( "a" ).css( "background-color", "#BADA55" );
</script>
</body>
</html>