| CARVIEW |
Select Language
HTTP/2 301
content-length: 162
content-type: text/html
date: Tue, 14 Oct 2025 21:22:54 GMT
location: https://developer.mozilla.org/en-US/docs/Web/API/TextMetrics/fontBoundingBoxDescent
server: nginx
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: AAwnv3LtxPTHBORhOw9k4vuNCK-Q7VgfuVrV-6Fjt6HqBPLMIOjiMNX0-xRiSlAXp_8M9kXg
cache-control: public, max-age=3600
expires: Tue, 14 Oct 2025 22:22:55 GMT
last-modified: Tue, 14 Oct 2025 01:07:20 GMT
etag: W/"0cd35dc23ac9f4f9e95d00f937ac93a7"
x-goog-generation: 1760404040792585
x-goog-metageneration: 1
x-goog-stored-content-encoding: identity
x-goog-stored-content-length: 137965
x-goog-meta-goog-reserved-file-mtime: 1760402431
x-goog-hash: crc32c=B7t4sA==, md5=DNNdwjrJ9PnpXQD5N6yTpw==
x-goog-storage-class: STANDARD
accept-ranges: none
alt-svc: h3=":443"; ma=2592000,h3-29=":443"; ma=2592000
alt-svc: clear
referrer-policy: strict-origin-when-cross-origin
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-XNBp89FG76amD8BqrJzyflxOF9PaWPqPqvJfKZPCv7M=' 'sha256-YCNoU9DNiinACbd8n6UPyB/8vj0kXvhkOni9/06SuYw=' 'sha256-PZjP7OR6mBEtnvXIZfCZ5PuOlxoDF1LDZL8aj8c42rw='; 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-XNBp89FG76amD8BqrJzyflxOF9PaWPqPqvJfKZPCv7M=' 'sha256-YCNoU9DNiinACbd8n6UPyB/8vj0kXvhkOni9/06SuYw=' 'sha256-PZjP7OR6mBEtnvXIZfCZ5PuOlxoDF1LDZL8aj8c42rw='; 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: 93bdb30bb86c28b5a029a68cb7f60e70
date: Tue, 14 Oct 2025 21:22:56 GMT
server: Google Frontend
via: 1.1 google
vary: Accept-Encoding
content-encoding: gzip
x-cache: miss
TextMetrics: fontBoundingBoxDescent property - Web APIs | MDN
Toggle sidebar
TextMetrics: fontBoundingBoxDescent property
Baseline
2023
Newly available
Since August 2023, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.
Note: This feature is available in Web Workers.
The read-only fontBoundingBoxDescent property of the TextMetrics interface returns the distance from the horizontal line indicated by the CanvasRenderingContext2D.textBaseline attribute to the bottom of the bounding rectangle of all the fonts used to render the text, in CSS pixels.
Value
A number, in CSS pixels.
Examples
The code below shows how you can get the fontBoundingBoxDescent for text in a particular font.
js
const canvas = document.createElement("canvas");
const ctx = canvas.getContext("2d");
ctx.font = "25px serif";
const text = "Foo";
const textMetrics = ctx.measureText(text); // returns TextMetrics object
const descentCssPixels = textMetrics.fontBoundingBoxDescent;
<p id="log"></p>
const log = document.getElementById("log");
log.innerText = `fontBoundingBoxDescent: ${descentCssPixels}`;
The descent in CSS pixels for the text "Foo" in a 25px serif font is shown below.
Specifications
| Specification |
|---|
| HTML # dom-textmetrics-fontboundingboxdescent-dev |
Browser compatibility
Loading…