Rule Definition
Another form of browser sniffing; unreliable and obsolete.

Remediation
Use feature detection (e.g., checking if a method exists) or standards-based behavior; avoid IE-only branches.

Violation Code Sample

if (navigator.appName === "Microsoft Internet Explorer") {
  enableIEWorkaround();
}

Fixed Code Sample

if (!("addEventListener" in window)) {
  enableLegacyWorkaround();
}

– MDN – Navigator.appName (deprecated): https://developer.mozilla.org/en-US/docs/Web/API/Navigator/appName – MDN – Browser detection is discouraged: https://developer.mozilla.org/en-US/docs/Web/HTTP/Browser_detection_using_the_user_agent – WHATWG – Navigator object (legacy compatibility): https://html.spec.whatwg.org/multipage/system-state.html#the-navigator-object