HTML Code

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta http-equiv="Content-Security-Policy" content="default-src 'none'; script-src 'unsafe-inline'; style-src 'unsafe-inline'; img-src 'none'">
  <title>onsecuritypolicyviolation</title>
</head>
<body>
  <pre id="out">waiting…</pre>
  <script>
    var out = document.getElementById("out");
    function show(e) {
      out.textContent =
        "violation: " + e.violatedDirective +
        " · " + e.blockedURI;
    }
    window.onsecuritypolicyviolation = show;
    window.addEventListener("securitypolicyviolation", show);
    var img = new Image();
    img.src = "https://example.com/blocked.png";
  </script>
</body>
</html>

Lines: 0 | Characters: 0

Live Preview Auto-refresh on Run

Element securitypolicyviolation — window handler (Try It)