JSFiddle - React, Tailwind, and code Playground

HTML

<!doctype html>

<html>

  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1">
  </head>

  <body>
    <div class="tab">
      <button class="tablinks" onclick="openCity(event, 'PageOne')">Page One</button>
      <button class="tablinks" onclick="openCity(event, 'PageTwo')">Page Two</button>
      <button class="tablinks" onclick="openCity(event, 'PageThree')">Page Three</button>
    </div>
    <div id="PageOne" class="tabcontent">
      <h3>London</h3>
      <p>London is the capital city of England.</p>
    </div>
    <div id="PageTwo" class="tabcontent">
      <h3>Paris</h3>
      <p>Paris is the capital of France.</p>
    </div>
    <div id="PageThree" class="tabcontent">
      <div id="siteloader"></div>
    </div>
  </body>

</html>

CSS

body {
  font-family: Arial;
}

/* Style the tab */
.tab {
  overflow: hidden;
  border: 1px solid #ccc;
  background-color: #f1f1f1;
}

/* Style the buttons inside the tab */
.tab button {
  background-color: inherit;
  float: left;
  border: none;
  outline: none;
  cursor: pointer;
  padding: 10px 10px;
  transition: 0.3s;
  font-size: 12px;
}

/* Change background color of buttons on hover */
.tab button:hover {
  background-color: #ddd;
}

/* Create an active/current tablink class */
.tab button.active {
  background-color: #ccc;
}

/* Style the tab content */
/*  <button class="tabLinks" onclick="loadURL('http://insider.palaceentertainment.com')">Insider URL</button> */
/*  <button class="tabLinks" onclick="loadContent('url_content', 'http://www.msn.com')">MSN</button> */
.tabcontent {
  display: none;
  padding: 6px 8px;
  border: 1px solid #ccc;
  border-top: none;
}

JavaScript

function loadContent(id, url) {
  var node = document.getElementById(id);
  node.innerHTML = url;
}

function openCity(evt, cityName) {
  var i, tabcontent, tablinks;

  if (cityName == 'PageThree') {
    alert("Load External Content");
    $("#siteloader").html('<iFrame src="http://validator.w3.org/">');
  }

  tabcontent = document.getElementsByClassName("tabcontent");
  for (i = 0; i < tabcontent.length; i++) {
    tabcontent[i].style.display = "none";
  }
  tablinks = document.getElementsByClassName("tablinks");
  for (i = 0; i < tablinks.length; i++) {
    tablinks[i].className = tablinks[i].className.replace(" active", "");
  }
  document.getElementById(cityName).style.display = "block";
  evt.currentTarget.className += " active";
}