add bootstrap to iframe code example

Example: bootstrap iframe

Copy Code<pre><div class="iframe-container">
  <iframe width="650" height="180" style="border: 2px solid #cccccc;" src="https://thingspeak.com/channels/929272/charts/1?bgcolor=%23ffffff&color=%23d62020&dynamic=true&results=60&type=line&update=15"></iframe>
</div>
<br/>
<div class="iframe-container">
  <iframe width="650" height="180" style="border: 2px solid #cccccc;" src="https://thingspeak.com/channels/929272/charts/2?bgcolor=%23ffffff&color=%23d62020&dynamic=true&results=60&type=line&update=15"></iframe>
</div>
<br/>
<div class="iframe-container">
  <iframe width="650" height="180" style="border: 2px solid #cccccc;" src="https://thingspeak.com/channels/929272/charts/8?bgcolor=%23ffffff&color=%23d62020&dynamic=true&results=60&type=line&update=15"></iframe>
</div>
<div class="wrapper" align="center">
  <div class="btn-group" id="toggle_event_editing">
    <button type="button" class="btn btn-danger locked_active">OFF</button>
    <button type="button" class="btn btn-success unlocked_inactive">ON</button>
  </div>
  <div class="alert alert-info" id="switch_status">Switched off.</div>
</div>
<br/>