JSFiddle - React, Tailwind, and code Playground

HTML

<iframe src="http://api.jquery.com/" width="80%" height="400" id='frameDemo'></iframe><BR>
 <button id="get">Get</button>

JavaScript

$(document).ready(function(){
 $('#get').live('click', function() {
                                  
    var currentIFrame = $('#frameDemo');
    currentIFrame.contents().find("a").css("background-color","#BADA55");
                                
    alert ("done")
});
});