ResizeObserver: unobserve() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2020.

The unobserve() method of the ResizeObserver interface ends the observing of a specified Element or SVGElement.

Syntax

js
unobserve(target)

Parameters

target

A reference to an Element or SVGElement to be unobserved.

Return value

None (undefined).

Exceptions

None.

Examples

The following snippet is taken from the resize-observer-text.html (see source) example:

js
const resizeObserver = new ResizeObserver((entries) => {
  for (const entry of entries) {
    if (entry.contentBoxSize) {
      // Checking for chrome as using a non-standard array
      if (entry.contentBoxSize[0]) {
        h1Elem.style.fontSize = `${Math.max(
          1.5,
          entry.contentBoxSize[0].inlineSize / 200,
        )}rem`;
        pElem.style.fontSize = `${Math.max(
          1,
          entry.contentBoxSize[0].inlineSize / 600,
        )}rem`;
      } else {
        h1Elem.style.fontSize = `${Math.max(
          1.5,
          entry.contentBoxSize.inlineSize / 200,
        )}rem`;
        pElem.style.fontSize = `${Math.max(
          1,
          entry.contentBoxSize.inlineSize / 600,
        )}rem`;
      }
    } else {
      h1Elem.style.fontSize = `${Math.max(
        1.5,
        entry.contentRect.width / 200,
      )}rem`;
      pElem.style.fontSize = `${Math.max(1, entry.contentRect.width / 600)}rem`;
    }
  }
  console.log("Size changed");
});

resizeObserver.observe(divElem);

checkbox.addEventListener("change", () => {
  if (checkbox.checked) {
    resizeObserver.observe(divElem);
  } else {
    resizeObserver.unobserve(divElem);
  }
});

Specifications

Specification
Resize Observer
# dom-resizeobserver-unobserve

Browser compatibility

desktop mobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
unobserve
Chrome – Full support
Chrome 64 (Release date: 2018-01-23)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 69 (Release date: 2019-09-03)
footnote Full support
Opera – Full support
Opera 51 (Release date: 2018-02-07)
footnote Full support
Safari – Full support
Safari 13.1 (Release date: 2020-03-24)
footnote Full support
Chrome Android – Full support
Chrome Android 64 (Release date: 2018-01-23)
footnote Full support
Firefox for Android – Full support
Firefox for Android 79 (Release date: 2020-07-28)
footnote Full support
Opera Android – Full support
Opera Android 47 (Release date: 2018-07-23)
footnote Full support
Safari on iOS – Full support
Safari on iOS 13.4 (Release date: 2020-03-24)
footnote Full support
Samsung Internet – Full support
Samsung Internet 9 (Release date: 2018-09-15)
footnote Full support
WebView Android – Full support
WebView Android 64 (Release date: 2018-01-23)
footnote Full support
WebView on iOS – Full support
WebView on iOS 13.4 (Release date: 2020-03-24)
footnote Full support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support