HTTP/2 301
server: nginx
date: Wed, 23 Jul 2025 10:07:37 GMT
content-type: text/html
content-length: 162
location: https://developer.mozilla.org/en-US/docs/Web/API/HTMLTrackElement/default
strict-transport-security: max-age=60; includeSubDomains
via: 1.1 google
alt-svc: h3=":443"; ma=2592000,h3-29=":443"; ma=2592000
HTTP/2 200
content-type: text/html
x-guploader-uploadid: ABgVH891XIsClEHvFBJZpdoLmffyUNsTHOU8GQHVPSdkBtloZDL0YazP3cCperqvzSCP9yd7gp0hgyc
cache-control: public, max-age=3600
expires: Wed, 23 Jul 2025 11:07:37 GMT
last-modified: Wed, 23 Jul 2025 00:45:39 GMT
etag: W/"5281f12ecc97f132201d44af186abfde"
x-goog-generation: 1753231538900902
x-goog-metageneration: 1
x-goog-stored-content-encoding: identity
x-goog-stored-content-length: 67271
x-goog-meta-goog-reserved-file-mtime: 1753230353
x-goog-hash: crc32c=2ul13g==, md5=UoHxLsyX8TIgHUSvGGq/3g==
x-goog-storage-class: STANDARD
accept-ranges: none
alt-svc: h3=":443"; ma=2592000,h3-29=":443"; ma=2592000
alt-svc: clear
x-content-type-options: nosniff
strict-transport-security: max-age=63072000
content-security-policy: default-src 'self'; script-src 'report-sample' 'self' 'wasm-unsafe-eval' https://www.google-analytics.com/analytics.js https://www.googletagmanager.com/gtag/js assets.codepen.io production-assets.codepen.io https://js.stripe.com 'sha256-EehWlTYp7Bqy57gDeQttaWKp0ukTTEUKGP44h8GVeik=' 'sha256-XNBp89FG76amD8BqrJzyflxOF9PaWPqPqvJfKZPCv7M='; script-src-elem 'report-sample' 'self' 'wasm-unsafe-eval' https://www.google-analytics.com/analytics.js https://www.googletagmanager.com/gtag/js assets.codepen.io production-assets.codepen.io https://js.stripe.com 'sha256-EehWlTYp7Bqy57gDeQttaWKp0ukTTEUKGP44h8GVeik=' 'sha256-XNBp89FG76amD8BqrJzyflxOF9PaWPqPqvJfKZPCv7M='; style-src 'report-sample' 'self' 'unsafe-inline'; 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://*.google-analytics.com https://*.analytics.google.com https://*.googletagmanager.com https://incoming.telemetry.mozilla.org https://observatory-api.mdn.allizom.net https://observatory-api.mdn.mozilla.net https://api.github.com/search/issues stats.g.doubleclick.net https://api.stripe.com; font-src 'self'; frame-src 'self' interactive-examples.mdn.mozilla.net interactive-examples.mdn.allizom.net mdn.github.io live-samples.mdn.mozilla.net live-samples.mdn.allizom.net *.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 *.googleusercontent.com *.gravatar.com mozillausercontent.com firefoxusercontent.com profile.stage.mozaws.net profile.accounts.firefox.com developer.mozilla.org mdn.dev interactive-examples.mdn.mozilla.net interactive-examples.mdn.allizom.net wikipedia.org upload.wikimedia.org https://mdn.github.io/shared-assets/ https://mdn.dev/ https://*.google-analytics.com https://*.googletagmanager.com www.gstatic.com; 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-options: DENY
origin-trial: AxVILwizhbMjxFeHOn1P3R8niO1RJY/smaK4B4d1rLzc1gTaxtXMSaTi+FoigYgCw40uFRDwFcEAeqDR+vVLOW4AAABfeyJvcmlnaW4iOiJodHRwczovL2RldmVsb3Blci5tb3ppbGxhLm9yZyIsImZlYXR1cmUiOiJQcml2YXRlQXR0cmlidXRpb25WMiIsImV4cGlyeSI6MTc0MjA3OTYwMH0=
x-cloud-trace-context: 80058eca54cbec127d35d4fd69085b26
date: Wed, 23 Jul 2025 10:07:38 GMT
server: Google Frontend
via: 1.1 google
vary: Accept-Encoding
content-encoding: gzip
x-cache: miss
HTMLTrackElement: default property - Web APIs | MDN
HTMLTrackElement: default property Baseline Widely available
The default
property of the HTMLTrackElement
interface represents whether the track will be enabled if the user's preferences do not indicate that another track would be more appropriate. It reflects the <track>
element's boolean default
attribute, returning true
if present and false
otherwise.
const trackElement = document.getElementById("exampleTrack");
console.log(trackElement.default);
trackElement.default = true;