index.html

<!DOCTYPE html>
<html>

<head>
  <title>iframe-browser</title>
  <link rel="stylesheet" type="text/css" href="style.css">
  <script type="text/javascript" src="script.js"></script>
</head>

<body>
  <div class="tab">
    Address:&nbsp;<input type="text" id="address"></input>
    <button onclick="load()" class="btn">Load</button>
    <button onclick="newtab()" class="btn">New tab</button><br>
    <div id="tabbtns">
      <button class="btn active" onclick="openTab(1)" id="tabb1">Tab 1</button>
    </div>
  </div>
  <div id="tabs">
    <div id="tab1" class="tabcontent" style="display:block">
      <span onclick="close()" class="topright">[x]</span>
      <span onclick="fullscreen(byId('iweb'+currentTab))" class="topright2">[+]</span>
      <iframe src="" height="500" width="1000" id="iweb1" allowfullscreen></iframe>
    </div>
  </div>
</body>

</html>