Error: Permission denied to access property "x"

The JavaScript exception "Permission denied to access property" occurs when there was an attempt to access an object for which you have no permission.

Message

DOMException: Blocked a frame with origin "x" from accessing a cross-origin frame. (Chromium-based)
DOMException: Permission denied to access property "x" on cross-origin object (Firefox)
SecurityError: Blocked a frame with origin "x" from accessing a cross-origin frame. Protocols, domains, and ports must match. (Safari)

Error type

What went wrong?

There was attempt to access an object for which you have no permission. This is likely an <iframe> element loaded from a different domain for which you violated the same-origin policy.

Examples

No permission to access document

<!DOCTYPE html>
<html lang="en-US">
  <head>
    <iframe id="myframe" src="http://www1.w3c-test.org/common/blank.html"></iframe>
    <script>
      onload = function() {
        console.log(frames[0].document);
        // Error: Permission denied to access property "document"
      }
    </script>
  </head>
  <body></body>
</html>

See also