Security Report Summary
A
Site: https://developer.mozilla.org/en-US/docs/Web/API/Document_Object_Model/Events
IP Address: 199.232.25.91
Report Time: 08 Oct 2026 11:14:46 UTC
Headers:
  • X-Content-Type-Options
  • Content-Security-Policy
  • X-Frame-Options
  • Referrer-Policy
  • Strict-Transport-Security
  • Permissions-Policy
Advanced:
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Missing Headers
Permissions-PolicyPermissions Policy is a new header that allows a site to control which features and APIs can be used in the browser.
Raw Headers
HTTP/2200
cache-controlpublic, max-age=3600
x-content-type-optionsnosniff
content-security-policydefault-src 'self'; script-src 'report-sample' 'self' 'wasm-unsafe-eval' assets.codepen.io production-assets.codepen.io https://js.stripe.com transcend-cdn.com 'sha256-XNBp89FG76amD8BqrJzyflxOF9PaWPqPqvJfKZPCv7M=' 'sha256-YCNoU9DNiinACbd8n6UPyB/8vj0kXvhkOni9/06SuYw=' 'sha256-PZjP7OR6mBEtnvXIZfCZ5PuOlxoDF1LDZL8aj8c42rw='; script-src-elem 'report-sample' 'self' 'wasm-unsafe-eval' assets.codepen.io production-assets.codepen.io https://js.stripe.com transcend-cdn.com 'sha256-XNBp89FG76amD8BqrJzyflxOF9PaWPqPqvJfKZPCv7M=' 'sha256-YCNoU9DNiinACbd8n6UPyB/8vj0kXvhkOni9/06SuYw=' 'sha256-PZjP7OR6mBEtnvXIZfCZ5PuOlxoDF1LDZL8aj8c42rw='; style-src 'report-sample' 'self' 'unsafe-inline' transcend-cdn.com; object-src 'none'; base-uri 'self'; connect-src 'self' developer.allizom.org bcd.developer.allizom.org bcd.developer.mozilla.org updates.developer.allizom.org updates.developer.mozilla.org https://incoming.telemetry.mozilla.org https://observatory-api.mdn.allizom.net https://observatory-api.mdn.mozilla.net telemetry.transcend.io telemetry.us.transcend.io transcend-cdn.com https://api.github.com/search/issues https://api.stripe.com; font-src 'self'; frame-src 'self' mdn.github.io *.mdnplay.dev *.mdnyalp.dev *.play.test.mdn.allizom.net https://v2.scrimba.com https://scrimba.com jsfiddle.net www.youtube-nocookie.com codepen.io survey.alchemer.com https://js.stripe.com; img-src 'self' data: *.githubusercontent.com *.gravatar.com mozillausercontent.com firefoxusercontent.com profile.stage.mozaws.net profile.accounts.firefox.com developer.mozilla.org mdn.dev wikipedia.org upload.wikimedia.org https://mdn.github.io/shared-assets/ https://mdn.dev/; manifest-src 'self'; media-src 'self' archive.org videos.cdn.mozilla.net https://mdn.github.io/shared-assets/; child-src 'self'; worker-src 'self';
x-frame-optionsDENY
x-guploader-uploadidAP6rU81YUEWkInt7vtaLLcT0Eb_XlKtFglo7i75J1DBuh6dgidOiNWE6wtQitm9ZUeLoWpLksFiicp8
x-goog-hashcrc32c=f4t4mA==, md5=Z9DNKxAfQ+XkpyZj14w55g==
x-goog-storage-classSTANDARD
referrer-policystrict-origin-when-cross-origin
strict-transport-securitymax-age=63072000
etag"67d0cd2b101f43e5e4a72663d78c39e6"
x-cloud-trace-context7973e70146d1d12394597b25295a6618
x-goog-metageneration1
x-goog-stored-content-encodingidentity
last-modifiedThu, 08 Oct 2026 01:17:03 GMT
via1.1 google, 1.1 varnish, 1.1 varnish, 1.1 varnish
x-goog-generation1791422223303101
x-goog-stored-content-length188920
expiresThu, 08 Oct 2026 04:32:52 GMT
content-typetext/html
serverGoogle Frontend
x-goog-meta-goog-reserved-file-mtime1791421158
content-encodinggzip
accept-rangesbytes
dateThu, 08 Oct 2026 11:14:46 GMT
age3185
x-served-bycache-par-lfpb1150097-PAR, cache-par-lfpb1150097-PAR, cache-par-lfpb1150022-PAR, cache-dub4379-DUB
x-cacheMISS, HIT, MISS
x-cache-hits0, 6, 0
x-timerS1791458087.758733,VS0,VE19
varyAccept-Encoding
content-length28184
Upcoming Headers
Cross-Origin-Embedder-PolicyCross-Origin Embedder Policy allows a site to prevent assets being loaded that do not grant permission to load them via CORS or CORP.
Cross-Origin-Opener-PolicyCross-Origin Opener Policy allows a site to opt-in to Cross-Origin Isolation in the browser.
Cross-Origin-Resource-PolicyCross-Origin Resource Policy allows a resource owner to specify who can load the resource.
Additional Information
x-content-type-optionsX-Content-Type-Options stops a browser from trying to MIME-sniff the content type and forces it to stick with the declared content-type. The only valid value for this header is "X-Content-Type-Options: nosniff".
content-security-policyContent Security Policy is an effective measure to protect your site from XSS attacks. By whitelisting sources of approved content, you can prevent the browser from loading malicious assets. Analyse this policy in more detail. You can sign up for a free account on Report URI to collect reports about problems on your site.
x-frame-optionsX-Frame-Options tells the browser whether you want to allow your site to be framed or not. By preventing a browser from framing your site you can defend against attacks like clickjacking.
referrer-policyReferrer Policy is a new header that allows a site to control how much information the browser includes with navigations away from a document and should be set by all sites.
strict-transport-securityHTTP Strict Transport Security is an excellent feature to support on your site and strengthens your implementation of TLS by getting the User Agent to enforce the use of HTTPS.
serverServer value has been changed. Typically you will see values like "Microsoft-IIS/8.0" or "nginx 1.7.2".