title: Why Chrome cannot access to external stylesheet using insertRule with Javascript?
body: <p>I have a HTML file, and linked in the head, an external stylesheet, and both of them are in the same folder. There are only one stylesheet. In the bottom of the body, i have a script:</p>
  
  <pre><code>document.styleSheets[0].insertRule(".example{position: relative}", 0);
  </code></pre>
  
  <p>But i get this error message (suprisingly only on Chrome 64, on FireFox, Safari mobile and Chrome mobile works well): </p>
  
  <p><strong><code>Uncaught DOMException: Failed to execute 'insertRule' on 'CSSStyleSheet': Cannot access StyleSheet to insertRule</code></strong> </p>
  
  <p>Why?</p>