title: Failed to load data inside of iFrame
body: <p>I tried to fetch the URL of an old website, and an error happened:</p>
  
  <pre><code>Fetch API cannot load http://xyz.
  No 'Access-Control-Allow-Origin' header is present on the requested resource.
  Origin 'http://abc' is therefore not allowed access.
  If an opaque response serves your needs, set the request's mode to 'no-cors'
  to fetch the resource with CORS disabled.
  </code></pre>
  
  <p>my code looks like this</p>
  
  <pre><code>render(){
      return (
         &lt;div&gt;
            &lt;iframe src="http://localhost:8080/.../StockExchangeWidget.html" /&gt;
         &lt;/div&gt;
      )
  }
  </code></pre>
  
  <p>when I load this outside of iFrame, everything is OK, but when I try to load it with iFrame well then I get lot's of errors, but only for data for charts, as you can see the frame and buttons are loaded.</p>
  
  <p><a href="https://i.stack.imgur.com/5ZELJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5ZELJ.png" alt="enter image description here"></a></p>
  
  <p>I'm also getting WebSocket error when I try to load HTML page over url inside of 
  WebSocket connection to 'wss://widgetdata.tradingview.com/socket.io/websocket?from=widgetembed%2F&amp;date=2018_06_09-17_59' failed: Error during WebSocket handshake: Unexpected response code: 403</p>