Web/API/ResizeObserverEntry/target

The target read-only property of the ResizeObserverEntry interface returns a reference to the Element or SVGElement that is being observed.

Syntax

var element = ResizeObserverEntry.target;
var svgElement = ResizeObserverEntry.target;

Value

An Element or SVGElement representing the element being observed.

Examples

The following snippet is taken from the [[../../../../../../../mdn.github.io/dom-examples/resize-observer/resize-observer-border-radius|resize-observer-border-radius.html]] (see source) example. This example includes a green box, sized as a percentage of the viewport size. When the viewport size is changed, the box's rounded corners change in proportion to the size of the box. We could just implement this using border-radius with a percentage, but that quickly leads to ugly-looking elliptical corners; this solution gives you nice square corners that scale with the box size.

To grab a reference to the observed element so we can update its border-radius value after each change, we make use of the target property of each entry —  entry.target.style.borderRadius.

const resizeObserver = new ResizeObserver(entries => {
  for (let entry of entries) {
    if(entry.contentBoxSize) {
      entry.target.style.borderRadius = Math.min(100, (entry.contentBoxSize.inlineSize/10) +
                                                      (entry.contentBoxSize.blockSize/10)) + 'px';
    } else {
      entry.target.style.borderRadius = Math.min(100, (entry.contentRect.width/10) +
                                                      (entry.contentRect.height/10)) + 'px';
    }
  }
});

resizeObserver.observe(document.querySelector('div'));

Specifications

Specification	Status	Comment
Resize ObserverThe definition of 'target' in that specification.	Editor's Draft	Initial definition.

Browser compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
target	Chrome Full support 64	Edge Full support 79	Firefox Full support 69	IE No support No	Opera Full support Yes	Safari No support No	WebView Android Full support 64	Chrome Android Full support 64	Firefox Android No support No	Opera Android Full support Yes	Safari iOS No support No	Samsung Internet Android Full support 9.0

Legend

Full support  

Full support

No support  

No support

ResizeObserverEntry.target by Mozilla Contributors is licensed under CC-BY-SA 2.5.